Need help with diagnosis on screen/GPU issue.

[Dave_07]

Hi, I need some advice on a weird issue that just started today. Basically one half of the image on my primary AOC monitor seems to have some vertical blue/purple line artifacting going on. But my second LG monitor is not displaying any such issue. And I need some advice on how to interpret the results of some testing i've done.

Here is an example image from a page web page on Video RAM artifacts:



If you look at this picture you can see some faint blue/purple vertical bars. They are most easily visible in the upper right hand side of the image. You can see one extending from the top of the letter F in the the word LIFE to the top of the image.

What i'm seeing is very similar to the example image above, only instead of it being individual vertical bars, it's just basically the whole right half of the AOC monitor looks like that, and it is most visible against black colors on screen. But my second LG monitor isn't displaying any such artifacting. (Both monitors are connected to the master GPU in SLI setup, with the AOC monitor via Display Port connection @120Hz, and the LG monitor @60Hz via HDMI connection)

Now when I found the web page the example image is from (link to page) I just assumed it was the primary GPU dieing, since the GPU's have had an overclock on them for a few months. So I wanted to test to see if it was the GPU it's self and not the actual monitor, since my second LG monitor is displaying no such artifacting. And if it is the GPU then why is the issue not appearing on the second monitor aswell.

So I disabled SLI and swapped the AOC monitor to the second GPU and left the LG monitor on the first GPU. So now the AOC monitor was on a completely different separate GPU. But it sill had the vertical blue line artifacting even on the second GPU and the LG monitor remained fine with no artifacting.

Then upon reconfiguring everything back after that testing, I noticed that reducing the refresh rate of the AOC monitor from my normal 120Hz to 100Hz seemed to make the artifacting much less noticeable/visible. At 100Hz you can only really see it if the colour mix on screen is just the right shade of grey or white. In any other colors you can't see it, and crucially it doesn't appear in any blacks on screen anymore.

So this kind of makes me think it's the monitor that's dieing and not the GPU's. Or maybe the display port cable. Either that or both of the GPU's have just got a hardware issue that causes this artifatcing, but lower refresh rates hide it ?

I'm kind of stumped. Not sure if it's the GPU's or the monitor. My gut is telling me it's the GPU's. But the fact that the LG monitor is artifact free, and lowering the refresh rate on the AOC monitor reduces the artifacting, seems to indicate that i'm missing something. As if it is a hardware fault with both GPU's then how come only the AOC monitor is artifacting and the LG monitor is fine. Also could a dieing display port cable produce this kind of artifacting ?

This is the AOC monitor : G-sync AOC G2460PG 1080p

Thanks for any advice.

[KeyboardDemon]

You have given 2 rig configs in your signature, to isolate the monitor as the cause I would disconnect it from the new rig and connect it to the old rig to see if the problems continue to show on it.

[Dave_07]

Sorry, I updated my sig. The old rig, I don't have access to it anymore, so can't test the monitor on that one unfortunately.

[KeyboardDemon]

In that case, do you either have a laptop or alternative computer that you can test the monitor with or another graphics card that you can swap out with both of your current cards in order to be able to eliminate all possibilities?

I would say that, from what you have said it does sound like the monitor, but it is worth doing as much as you can to prove it to yourself first, just in case it's something else.

[Dave_07]

Yeah, thank you Demon. Thats what I want to do really. Really need to determine for sure whether it is the monitor or GPUs, as it will save alot of time and hassle with needless RMA's. I've been trying to find something else to test the monitor on today. I have a spare laptop, but it doesn't have a DP connection. I took the monitor to a friends place aswell, but turned out his GPU only had DVI and HDMI ports. I even went to a neighbors house to check their PC but they have quite an old system an it only had a VGA port.

I never thought it would be so hard to find another system with a DP connection to just test the monitor on lol. All I need is 10 mins with any fairly modern system that has a DP connection.

Also having tested to see what the artifacting looks like in a few games now, it seems like it's kind of dynamic. But it's hard to tell. Which makes it look like it's a GPU issue. But i've never heard of GPU artifacts only effecting half of a screen image. In fact all the research on GPU artifacting i've done today seems to suggest that if a GPU has a hardware fault that causes artifacting to appear on screen, then it always effects the whole image, and wouldn't only effect half of the on screen image in this way.

I guess if I can't determine whether it's the monitor or the GPU's it's going to be hard to proceed with an RMA process. Only thing I can think of is to buy a cheap DP monitor and test that on the system. But first I think I might just get a new DP cable just to make sure it's not my existing cable at fault.

There is also a small independent computer repair shop near by. I might ask them if I can take the monitor down there and just test it on a spare computer if they have one. Hopefully they will let me test it.

I have one important question though, that has really been bothering me. If it is both the GPU's that have just developed problems, possibly because of the overclock they had on them. Then if both GPU's are damaged, then wouldn't artifacting also be present on my second monitor aswell ??? or am I misunderstanding how artifacting works ?

Thanks.

[KeyboardDemon]

If you are near the North London area I might be able to help out.

[peterb]

Unlikely that both GPUs would develop identical faults at the same time, that only affects one monitor. On the basis of the information given, my money is on the monitor developing a fault in the display driver electronics.

[Dave_07]

If you are near the North London area I might be able to help out.

Cheers Demon, really appreciate the offer. But i'm way down in the south west in Cornwall.

Unlikely that both GPUs would develop identical faults at the same time, that only affects one monitor. On the basis of the information given, my money is on the monitor developing a fault in the display driver electronics.

Yeah I have to agree. It's weird though because the artifacting looks so much like typical GPU artifacting, with the way it moves and changes and only appears in brown / grey colour areas of the screen. But quick google search showed apparently that LCD/LED monitors can indeed become faulty leading to on screen artifacts that pretty much look indistinguishable from typical GPU artifacting. Guess i've been such a CRT dinosaur for so long that whenever I see any pixely looking artifacting, it always scares the crap out of me, thinking the GPU's are about to catch on fire or die at any minute haha

Anyway, going to replace the cable and test the monitor. Hopefully it will be easily sorted now, and i'll post back results. Cheers guys, really appreciate your help.

+10 Internet Cookies to both of you

[Dave_07]

Update: For any future google searchers. Apparently what seemed to have happend is "heat expansion" on the DP cable pin. Which kinda makes sense because it has been very hot weather here past week. Just leave the monitor off for 24 hrs or just put a fan next to the cable like I did And hey presto, all is well again, fingers crossed, touch wood