3 Pieces to a puzzle

My PC is on 24/7, I am a developer who works at home and also likes to play games (logged 267 hours on Elden Ring, 134 hours on Dying Light 2, etc).

In early 2020 I had been reading about HDR (High Dynamic Range) and G-Sync/FreeSync monitors with refresh rates higher than the (then standard) 60 Hz, but those were all brand new technologies and none of the existing PC monitors supported all those technologies *at the same time*.

For that you needed the bandwidth provided by the new HDMI 2.1 standard which none of the PC monitors back then supported... NOR my - at the time - nVidia 2080 TI GPU.



But alas, in Q4 2020 nVidia would release the 3090, and this GPU would support HDMI 2.1. That was the first piece of the puzzle.

The second piece would obviously be a 4K monitor with HDMI 2.1 support. But what about the third piece?

I'm fundamentally a PC games player, but there were games exclusive to the PlayStation that I had been wanting to try out for a very long time: being a Dark Souls lover, mainly BloodBorne and the remake of Demon Souls.

As it turns out, Sony would also be releasing the PS5 in Q4 2020.

First piece of the puzzle: the Asus ROG Strix 3090 OC

The 3090 was quite expensive (little did I know the 4090 would later cost nearly double!) but besides the much needed HDMI 2.1 support it had something else that really interested me: 24 GB of GDDR6 memory (vs. 11 GB on the 2080 TI).

You see, I'm the kind of user that has a TON of tabs open at the same time on Firefox (and multiple Firefox windows). Either to sites I am constantly returning to, or to things I want to get back to later (and later might be months from now).

Since Firefox is hardware accelerated, all those tabs take up space in VRAM. To give you an idea, at this very moment I have 8 GB of VRAM being used by Firefox and the Windows DWM on my 4090. With 24 GB of VRAM available, that is nothing, but on the 2080 TI that meant being forced to close Firefox before being able to play most games at 4K.



Second piece of the puzzle: the LG CX

Back in December 2020 only the LG CX (a TV available in 48", 55" and 65" sizes) supported HDMI 2.1, 120 Hz refresh rate, VRR (Variable Refresh Rate, i.e. G-Sync/FreeSync) and HDR. It was also an OLED display- incredible image quality, deep blacks, and 1 ms response time.

Until then using a "normal" 60Hz 4K 43" LG IPS monitor as my main desktop monitor, I had been patiently waiting for something that supported all those new technologies. Unfortunately the first thing that came along - and actually worked - was not a computer monitor, but a TV.

I love my 43" 4K IPS monitor and I actually think that is the perfect size for 4K resolutions running at 100% DPI (if you actually want to be able to read text at 100% DPI, that is), and was a bit concerned a 48" might be a bit too big but I figured I would get used to it.

Given the size of the TV, I decided it was best to ask a friend to help me transport it home and in putting it together:



Pretty big for a PC monitor, as you can see

Third piece of the puzzle: the PS5

The PlayStation 5 console had been released a month earlier in November and that too supported - or would support - HDMI 2.1, 4K, HDR, VRR and 120 Hz. Despite the difficulty in getting a PS5 at the time due to the pandemic, I was lucky enough to get one barely two weeks after getting the CX.

And by lucky I mean REALLY lucky: there was a shortage of PS5's everywhere so big stores like Worten were giving you online access to the very limited stock - whenever new shipments came - on a first come first served base. Needless to say, the small stock would be gone in minutes, if not seconds.

A friend told me about Worten making a few units available later that night, but since I didn't know how the process worked, I decided to give them a call during the afternoon. Much to my surprise, the person I was talking to offered to reserve one PS5 for me right then and there. I could not believe my luck.

Being a PC games player, the PS5 is actually my first console ever.



And so in quick succession I got all the parts I needed: the 3090 in the second half of November, the LG CX in the first week of December and the PS5 two weeks later.

My 43" LG IPS monitor thus became my secondary monitor and the CX my primary. Having two huge > 40" 4K monitors on your desk is a sight to behold.



Running a TV as a computer monitor: the good, the bad and the ugly

So what was my first impression of the LG CX? To put it bluntly, I was immediately blown away.

There is NOTHING like OLED in terms of image quality: since each pixel lights up individually and emits its own light, there is no need for a backlight nor any dimming zones as in LCD technology. With no backlight, blacks are accomplished by literally turning the pixel off, so what you get is a deep black with an amazing contrast, not the dark gray of regular LCD monitors.

The glossy coating of the TV also helps to make the image "pop out" right at you - it's a very reflective surface, but since I usually have the office darkened it did not bother me at all.

Add to that 120 Hz, HDR and VRR, and I was in monitor heaven. Except this wasn't a monitor, but a TV.



There were a lot of other things I liked about the CX: for instance, you could assign different inputs to long key presses on the magic remote (e.g. long press 1 to switch input to the PC, long press 2 to switch input to the PS5, long press 3 to switch to TV mode) and the TV notified you when another input had just become active, allowing you to switch to it at the press of a button if you so wished.

Being able to watch regular cable TV on the "monitor" was also a big plus, as was seamlessly performing firmware updates via WiFi.

Now, one of the problems of OLED is the risk of burn in/image retention, which can happen if you show static images (such as logos, game HUDs, etc) for long periods of time. Usually not much of a problem if you are mostly watching movies and playing games, but can become an issue if you spend a lot of time on something mostly static like the Windows desktop...

I was acutely aware about the burn in risk when I got this TV - especially given what I do and how much time I spend on the PC - and was prepared for what that might entail (i.e. a TV lasting less than a handful of years). However, and for the first two years, I was VERY pleasantly surprised (more on this later as I did end up getting burn in, but I am partly to blame) - and given the time I spend in front of the PC, I would say that those 2 years would probably be equivalent to 4 years of 'normal usage' or more.

To help mitigate burn in LG introduced a handful of mechanisms: pixel shift, logo compensation, auto dimming and a pixel cleaner that runs automatically every x hours of screen utilization when you turn the TV on to get rid of image retention.

OLED technology has come a long way, but you still need to be a bit more careful with it than you would with any other display technology. I run Windows in dark mode, have a slideshow of dark wallpapers, try to avoid leaving bright static windows on the same position for a long time, and have my PC set to power off the screen after 10 minutes of inactivity.

Anyway, immediately after getting the CX I run into one of its MAJOR problems, at least for someone who spends a lot of time on the Windows desktop: the auto-dimming feature. After a while with no apparent (to the tv!) screen activity (for instance, you are reading or typing something) the screen will start to get dimmer and dimmer until text actually becomes hard to read.

For brightness to go back to normal you need to do something that changes the AVERAGE brightness level of the whole display area, like maximizing or minimizing a window or opening another window. Just wiggling an existing window around won't do it because that will not change the *average* brightness of the screen.

Since there is no option to turn this "feature" off in the regular LG settings, this makes the "vanilla" CX almost unusable for any kind of prolonged text work on the desktop, IMO.

Fortunately there is a way to turn auto-dimming off, but you do this at your own peril and you put your warranty in jeopardy: through a LG Service Remote.



After ordering a LG service remote from Amazon and finally disabling the auto-dimming 'feature' on the service menu, to me the biggest disadvantage of the CX as a monitor became, without a doubt, the lack of a standby feature. It would have been perfect otherwise.

Unlike a real computer monitor, the CX will NOT enter standby mode when the display goes off in Windows - instead it will show a bouncing 'No Signal' logo on the screen (which cannot be disabled) until the TV finally turns itself off 20 minutes or so later.

Once it has turned itself off, wiggling the mouse does not bring it back to life as it would a PC monitor, you must also use the remote to turn the TV back on. This is already quite annoying on a single monitor system, but it becomes almost a deal breaker on a multi-monitor system that is left running 24/7.

You see, when the CX turns itself off it disappears from the list of currently plugged in displays in Windows, unlike a regular monitor would in standby mode. This means ALL the windows on the CX screen are automatically moved to your secondary monitor, piling them up on whatever is already there.

Now, there are software workarounds (such as Monitor Keeper) which will remember the placement of windows and reposition them when you turn the CX back on (you need to run Monitor Keeper with admin privileges so it can also reposition windows of applications running elevated), but this - plus having to always turn the TV back on via the magic remote - is very clunky.

All this could be easily solved via firmware if only LG added a standby mode to any input identified as being connected to a PC instead of that 'No Signal' thing-a-magic followed by turning itself off 20 minutes later (which makes sense for TVs but not for computer monitors).

A possible alternative would be to disable monitor standby in Windows altogether and enable an all black screensaver, as that would turn all OLED pixels completely off - the TV only pulls 20 watts or so from the wall when the screen is completely black.

This would probably be a good solution if I was running a single monitor setup, OR if all my displays were OLED, but not when running a *multi-monitor* system where one of the monitors is a *LCD* screen.

Even when using an all black screensaver, the backlight on the LCD would still be on (actually my LG IPS monitor is smart enough to recognize a completely black screen after a while and turn the backlight off, but I did not know this at the time plus power consumption is definitely not the same as true standby).

As such, not only will the LCD monitor still consume a lot of power, as the lifespan of that monitor will be tremendously reduced: on a LCD monitor the backlight is usually the first to go.

Another drawback is that screen savers prevent the PC from entering Sleep mode (or at least the all black screensaver seems to under Windows 11).

Something else that became an issue - but wasn't at first - was the automatic pixel refresher. Initially it would run automatically after the TV turned itself off with only a prompt saying that pixel refresher had completed when you turned the TV back on, but after a firmware update it would only run the pixel refresher AFTER you turned the TV on (WTH?!):



I remember this warning started happening after one of the CX firmware updates, it did not happen until then.

It's stupid NOT because running the pixel refresher isn't necessary (it is!), but because the TV could run it silently WHILE THE TV IS OFF as it did before (off relatively speaking, since it is still connected to the wall and thus receiving power) instead of waiting until you turn it on because you're in a rush to watch something.

If I had to guess, I would say some marketing head at LG decided that it was better to force people to KNOW pixel refresher was actually happening - so they can't later claim the TV didn't do it (or something like that) - because until then it was doing it without prompting the user. A real PITA.

Anyway, after a long while of suffering trough this I watched a Linus Tech Tips video where he mentioned LGTV Companion, a wonderful piece of software capable of powering WebOS LG TVs on and off together with the PC.



With LGTV Companion the CX would automatically turn itself off when Windows told the displays to enter standby and, more importantly, back on when exiting standby. Likewise, the PC could enter and exit Sleep mode without the need to turn the CX back on via the remote.

This made using the CX on a multi-monitor environment where the PC is on 24/7 much more practical, but it was still a bit clunky: as the software turned the CX on and off, open windows would still move around all over the place and sometimes would not return to their proper positions (and this could happen to Winstep desktop modules too).

This was actually one of the things that motivated me to add the new 'Reset Reserved Screen Space' internal command, and to dig deeper as to why desktop modules and docks would return to their proper positions *most of the time* but sometimes failed to do so despite the multi-monitor profiles mechanism built into the Winstep applications (turns out the problem was not the number of currently active monitors changing but actually their Windows handles changing without the number of active monitors also changing).

Burn in rearing its ugly head for the first time

One thing I eventually noticed after installing LGTV Companion was that the Pixel Refresher prompt never appeared again. I assumed a new firmware update or something meant it was silently working in the background, but in retrospective what I think really happened is that LGTV Companion prevented the TV from turning off and therefore Pixel Refresher from running.

Without it and over time I started to see the effects of image retention, mostly because of the bright Quick Launch icons in the NextSTART taskbar. By the time I manually triggered a pixel refresh it was too late and burn in had permanently settled in - although it's only really noticeable on solid color backgrounds.

I blame myself for not noticing or not really caring about the lack of the pixel refresher event for such a long time - pretty sure that if pixel refresher had been regularly running as it should then the CX would have kept showing no signs of burn in for a very long time to come.

Nvidia's nvlddmkm driver crash galore

Something else I noticed after I started using the CX is that the nVidia driver would frequently crash (TDR event) when returning from monitor standby, which could be pretty annoying although the driver nearly always recovered properly (but not always). It NEVER crashed while playing a game or at any other situation, so it was not bad hardware or a GPU problem (and I was not overclocking my 4090 either, due to all the melting adapter reports).

As far as I could tell, it had something to do with the monitor standby event and the LG CX (it never happened with other monitors) and there were a metric TON of other users on the net complaining about the same problem but with no resolution (nvlddmkm can crash for an infinite variety of reasons, of course).

In the mean time I discovered that the 43" LG IPS monitor would actually turn the backlight off after a few seconds when running the All Black screen saver. By this point I was so sick of all the monitor standby issues - even with the LGTV Companion - that I decided to turn off Monitor Standby in the Windows Power Settings and use the screen saver method instead.

Of course, this did consume more power than simply putting the monitors into standby, and it also meant that the PC was no longer entering Sleep mode while I was away due to the screen saver being active. I felt the increase in my monthly utility bill, but despite this I still preferred the peace of mind of knowing that I would always be coming back to a desktop where the open windows would still be where I had left them last.

It was at this point that I started eyeballing the OLED PC monitors that had come out in the mean time, as I figured with those I no longer would have to wrestle with monitor standby issues.

At this point there were only two real contenders: the 42" ASUS ROG Swift OLED PG42UQ (pretty expensive at around 1,800€) and the 48" LG Ultragear 48GQ900-B OLED (usually around €1,400€ but often coming down in price to 1,200€ or less). Both monitors are matte rather than glossy, which is a bit of a shame for my preferences since I'm not too bothered with screen reflections here (I prefer the image "pop" that you get with the glossy OLED panels).





However I could not force myself to pull the trigger at those prices, as other than the standby issues, the CX was still outstanding PLUS it had all the functions of a real TV.

I eventually filtered out the Asus as despite having the same OLED panel as the LG, it had many users complaining about firmware and other HDR related issues. I know full well how terribly awful Asus can be in terms of software (Armoury Crate, cough cough).

The Ultragear on the other hand is a LG monitor with a LG OLED panel, and LG usually stands by their monitors. Pity it also was a 48" panel, since I would actually prefer a smaller 42" monitor like the Asus.

Then Black Friday came and suddenly I found myself staring at a page offering a brand new LG Ultragear 48GQ900-B for only 700€. The offer was too good to pass up, so I ended up ordering it - this has become another adventure so far, one which I will recount in my next post.

The LG Ultragear 48GQ900-B 48" OLED monitor

The only reasons I had to justify buying this monitor even at the heavily discounted price I did were convenience and a substantial reduction in my future electricity bill, as it otherwise wasn't much different from the CX - it was, in fact, inferior in terms of many other features (no cable TV, no Wifi, matte panel, no magic remote, no smart features, etc).

However, the frequent nVidia driver crashes with the CX whenever the PC entered Sleep mode and the TV turned itself off due to lack of proper PC standby support (which forced me to re-arrange my desktop every time I came back to it after a driver crash) had been a huge PITA, tolerable but bad enough to make me disable Sleep mode and have the PC running 24/7, and constantly sucking at least 200W from the wall.

With the Ultragear OLED being a PC monitor with proper Standby, these problems would all go away and I would be living happily ever after - no more nVidia driver crashes or Windows thinking that the monitor had been disconnected whenever it entered a power saving mode. I would be able to enable sleep mode on the PC again therefore making the new monitor pay for itself in a year with what I would be saving on my electricity bill.

So all good, right? Right????! Ah-ah, things in life are rarely that simple!



The Ultragear features three HDMI 2.1 ports and a single DisplayPort 1.4 input. I only use HDMI as the CX only has HDMI inputs and I had previously purchased three high quality 3 meter Orange 2.1 Variation HDMI cables that support 4K video at 120Hz and 8K at 60Hz.

One cable to connect the PC to the OLED, another to connect the PC to the 43" secondary IPS monitor and the third cable to connect the PS5 to the OLED.



The first issue I immediately run into when plugging in the Ultragear was our old friend the auto-dimming feature. Even though the LG Service remote DOES work with the Ultragear, the settings are completely different and I read that some users actually bricked their monitors while attempting to deactivate TPC (Temporal Peak Luminance Control).

Fortunately I had done my home work so I already knew about this and how to fix - so many users complained that LG eventually caved in and allowed brightness to be immediately restored on the Ultragear by simply moving the mouse pointer. This 100% fixed the problem, but it required the latest firmware, which my monitor obviously did not have yet.

While updating the firmware on the CX was super simple and could be done via Wifi with a single click of a button, the lack of Wifi on this monitor meant that I first had to connect it to the PC via USB, then download an App from LG called 'OnScreen Control'.

I absolutely *hated* that App. Had to delete a folder to get it to show up in English as it insisted in displaying in Portuguese (with no way to change that), it displayed as if my monitor scaling was set to 200% (with no way to change that) and the Firmware update process was completely non-intuitive! Have a look:



Run? Run what?! You mean "Update"?! "Can only update the monitor software after checking for Updates" ... Where exactly? There is no 'Update' button anywhere. Clicking either the Run or File Open buttons resulted in the following prompt, despite only having the Ultragear connected to the PC via USB:



Despite wanting to forget all about the whole awful process, I still remember that I had a ton of trouble getting it to work. Had to download another version and even had to *physically* disconnect the HDMI cable from the secondary LG IPS monitor as disconnecting it from the wall was simply not enough! Only then did the above prompt disappear and I was able to update the Ultragear's firmware.

So, thankfully that took care of the auto-dimming "feature". Now I could enjoy my new monitor entering standby and the PC sleep mode without a care in the world and... wait, did the nVidia driver just crash again after the monitor entered standby?!!

Nvidia's nvlddmkm driver crash galore YET AGAIN

Ok, so here is what was happening: about 1-2 minutes after powering off the screen (I know because I cross-checked with the Windows Event Viewer) the nVidia driver would sometimes crash (but not always). Most of the time it would recover on its own with a TDR (although it would nearly always mess up the display, sometimes in a way you could do nothing else but reset the PC), but - and much more serious - other times the PC would BSOD with DPC_WATCHDOG_VIOLATION or other similar blue screen error and reboot. Again this ONLY happened whenever the Ultragear was turned off by the Windows Power Management, the GPU was otherwise rock solid even when playing demanding 3D games or running graphic benchmarks/torture tests.

At first I had the PC set to turn the display off after 10 minutes and to enter sleep 5 minutes later. I tried turning off the option to put the display into standby (or set into to activate AFTER the PC should enter sleep) but Windows 11 requires it to be on AND before sleep starts in order for the PC to enter sleep. So I set the PC to enter BOTH monitor standby AND sleep at the same time.

This would work most of the time as the PC would enter sleep almost immediately after turning the display off, not giving enough time for the driver to crash, but sometimes an application would be running in the background (for instance, a backup) that would allow the display to be turned off but would not allow the PC to sleep until the operation was completed. In those cases it was almost certain that I would return to a crashed PC or some kind of display corruption after yet another TDR.

The feeling that I had just spent hundreds of Euros on a new monitor just to be worse off than I was before is NOT a pleasant one, trust me.

At the same time I was beginning to understand WHY the crashes were happening: you see, these new OLED PC monitors do support normal standby, but the actual Pixel Cleaning process (which only runs every few hours of use right after the display enters standby) for some reason needs to actually turn the display off, not sure if for hardware or firmware reasons.

This is different from normal standby as when returning from a pixel cleaning cycle the Windows desktop would act as if the Ultragear had been turned off with the power button (as it *always* happened in the case of the CX) with open windows being moved around all over the place while Monitor Keeper repositioned them for a two monitor configuration.

The crashes ONLY seemed to happen when a Pixel Refresher cycle was run and the display was actually turned off because of it (which mimics what the CX did). If no Pixel Refresher cycle needed to run while the Ultragear was in standby, nothing bad or out of the ordinary would happen.

So, at least I knew WHAT was causing it, but not WHY.

While searching the net for solutions (or just to feel I was not alone) and reading multiple similar reports by luck I came across a post where the user reported fixing his instability with a 4090 GPU by setting the Power Management Mode in the nVidia Control Panel 3D settings to 'Prefer Maximum Performance'.

This forces the core and memory clocks to always run at their maximum speeds even while on the Windows desktop - and also makes the PC consume 20-30W more at idle. But guess what?

If fixed the problem. No more nvlddmkm crashes, no more BSODs. The system is - finally! - rock solid at all times. The monitors now enter and exit standby without anything bad happening, even when Pixel Refresher runs. Those extra 20-30W are but a small price to pay for that peace of mind.

So, it appears the 4090 (not sure if this issue affects other GPUs) has some kind of low power/low clocks bug that is triggered by one of the monitors in a multiple monitor system being turned off while in standby mode (and this will usually only happen with OLED monitors, when they run a pixel refresh cycle).

Not sure if this also happens on a single monitor system, or if it is specific to LG OLED monitors/TVs, but if anyone reading this is suffering from this type of instability, at least this is one more thing to try.

120 Hz overclocked to 138Hz

Something this monitor has that the CX did not is the ability to overclock it to 138Hz (just turn on the relevant option in the monitor's menu). If you do it via DisplayPort 1.4 the color information gets compressed to 8 bit, but with HDMI 2.1 you get the full 10 bit, no losses.

As far as I can tell, the overclock to 138 Hz/FPS works great and without issues (at least when using a HDMI connection like I am).

Wow! Very informative! I wonder if the drivers from Nvidia were causing the problem. I'm glad you found a solution, but I wonder if running it at max will eventually cause a problem.

If you feel like trying it, install MSI Center https://www.msi.com/Landing/MSI-Center with the caveat that it can be buggy. By that, I mean on occasion, something can affect it and cause it to not open. It is a PITA to reinstall. I found the best way is to delete the correct folder (I forgot which one) in Program Files after uninstalling, then restart the PC before attempting to reinstall.

I don't know if you read this post I made a while back, but read the last paragraph in the OP. viewtopic.php?f=4&t=11901

4090 sudden black screen, GPU fans running at 100%

After fixing the TDR issues on monitor standby as described above the system has been running rock solid for weeks... until one day I exit a game and after a couple minutes idle on the desktop the screen suddenly goes black and GPU fans ramp up to 100%. PC stopped responding, nothing on the Event Viewer, only solution was to turn it off then back on again (and it would start up as if nothing had happened).

I had already experienced this a couple of times before but it was so rare that in the middle of all the TDRs etc I didn't pay much attention to it.

However, a few days later it happened again: not while playing the game but when the GPU returned to idle after exiting the game (I would understand if it happened WHILE playing the game, but rock steady when idle, rock steady while playing the game, and only black screens a bit after exiting the game while idle on the desktop?!). Then it happened again right after launching a game.

So I started looking for a cause. Turns out the culprit seems to be the new 12VHPWR connector, more specifically the tiny sense pins (I have a Cablemod 12VHPWR cable and it seems they have released a new version to tackle this very issue). If one or more of the sense pins stop making contact while the GPU is running, instant black screen with fans run at 100%. Watch this:



So, here is what I think was happening: while gaming the temperature of the 12VHPWR connector increased given that it had give or take 450W flowing through it, which made the metal in the sense pins expand (perfect contact). When returning from the game, the temperature went down quickly causing the metal to contract, which possibly caused one or more of the sense pins to stop making perfect contact with the GPU after a short while.

I took out the plug and firmly re-inserted it again (also inspected it for burn or melting signs, found none). So far no more black screens, let's hope it stays that way.

It's now 10 days later and I just wanted to confirm that there are no more black screens with fans running at 100%.

So, if you have a GPU with a 12VHPWR connector and you are suffering from this intermittent issue, start by making sure your cable is firmly and properly inserted all the way in. More likely than not this will be a power problem, so if that doesn't work check your PSU too.

Unfortunately since that last post I had two random instances of a black screen with fans at 100%, both times shortly after starting a game.