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Hd4870 flashing pixels

Last response: in Graphics & Displays
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Anonymous
April 30, 2010 10:47:10 PM

hey, recently while playing games i've noticed some flickering green pixels appearing on screen sometimes. after a while the flickering pixels slowly increase in number, and then the game hangs and vpu recover kicks in, after which the game either un-hangs or crashes, although whichever happens the pixels stop appearing afterwards until i reboot my computer. i don't think the card is overheating (45c idle, 50-55 load), the drivers are up-to-date and the memory/gpu clock are unchanged, does anyone know how to fix this?

here's an example of the problem, although it's usually not this bad: http://img25.imageshack.us/img25/6015/pixelsa.png

More about : hd4870 flashing pixels

May 1, 2010 1:40:42 AM

Well, i too have a similar problem but my guess is that it is game specific.. For me the same happens whenever i play I.G.I 2 and GTA: Vice City which are a good 8+ years old games already.. Never noticed it with the more recent titles.. My theory is that it is the case of GPU over efficiency.. These games i mentioned don't give that much a workout to a card as powerful as 4870 (the first time i played them was with onboard intel g845).. Moreover, due to the 1GB frame buffer, the card usually draws up a large scene and then has to sit idol until suddenly it has to draw again.. This switching must be causing the card to not respond as smoothly and thus hang after which it either recovers back to the game or the desktop.. This is just a theory.. I could solve the problem in I.G.I 2 somewhat by disabling the CPU multiplexing option in the bios.. Which games are you noticing such behaviour.? Based on that info we might be able to understand the reasons behind it..
May 1, 2010 1:47:21 AM

usually this would indicate an overheating card, download GPUz and check th temps the card is running at under load.

if they are getting too high, you may need to manually adjust fan speed to compensate.
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May 4, 2010 8:21:43 PM

welshmousepk said:
usually this would indicate an overheating card, download GPUz and check th temps the card is running at under load.

if they are getting too high, you may need to manually adjust fan speed to compensate.


the load temp is usually between 50-60c, fan speed has been set to 45% since i got the card

also sometimes weird jagged graphics flicker onscreen too, not sure if they're artifacts or whatever
May 5, 2010 5:15:31 AM

wpminnows said:
the load temp is usually between 50-60c, fan speed has been set to 45% since i got the card

also sometimes weird jagged graphics flicker onscreen too, not sure if they're artifacts or whatever


did you download GPUz and log temps?

its not really the GPU temp you need to be looking at, its the RAM and VRMs. they will be running much hotter than the GPU and possibly the source of the problem
May 5, 2010 4:08:39 PM

welshmousepk said:
did you download GPUz and log temps?

its not really the GPU temp you need to be looking at, its the RAM and VRMs. they will be running much hotter than the GPU and possibly the source of the problem


oh right

http://imgur.com/QwRr0.png

are these the temps you're talking about?
May 6, 2010 1:58:46 AM

yes, but we need to see them under load. run ATItools artifact scan or furmark, then look at those temps.

the 0 percent load temps tell us nothing.
May 6, 2010 6:31:39 AM

your Vram is hitting temps above 70c. not dangerous by any stretch, but given th age of the card it could be enough to cause problems.

try upping the fan speed to around 70 percent. run the test again, and hopefully the artifacting will have gone away.
May 6, 2010 6:57:04 AM

i tried upping the fan speed, the temps dropped by about 5c but the pixels and artifacting still appeared

they both seem to disappear until the next time i reboot after vpu recover kicks in, not sure if that means anything

thanks for the help btw
May 6, 2010 7:12:44 AM

temps only dropped by 5c?

thats really not the sort of drop i was expecting. I'm thinking that maybe the thermal pads have torn, and are no longer making proper contact with the chips. it gets a little complicated from there though, since you'd need to take the heatsink of the card to have a look.

the other thing you can try is downclocking the memory (or the core, but i don't think thats the problem) and then running a stress test. this should reduce some of the heat also. its not a permanent fix, but will at least identify the problem.

if downclocking + high fan speed doesn't make the problem disappear, then its almost certainly a hardware fault and won't be easily fixed (if it can be fixed at all)
is the card still under warranty?
May 6, 2010 4:35:06 PM

yeah, the card's still under warranty

how much should i downclock the memory to?
May 7, 2010 1:16:50 AM

bring it down by 200mhz just to run the test, and see how much temps drop. hopefully enough to stop the artifacting.

I think you will need to RMA the card though, as this is almost certainly a hardware fault. at least you are still under warranty.
May 7, 2010 8:14:07 AM

RMA the Card theres a big issue there. (OR maybe your power supply isnt adequate)

Good Luck, what brand are you using?
May 8, 2010 3:28:45 PM

xfx

is a 600w psu enough
May 8, 2010 4:22:22 PM

Should Be, How old is it?
May 8, 2010 5:29:33 PM

about 1 year old for the psu, only bought the card in january
May 9, 2010 10:03:22 AM

That is sad, could it not be the monitor causing the fault? maybe the refresh rate is to high or the monitors power supply is dying?
May 12, 2010 6:27:32 PM

fisshy said:
That is sad, could it not be the monitor causing the fault? maybe the refresh rate is to high or the monitors power supply is dying?


the monitor's newer than the card, refresh rate is 60hz, not sure if that's bad (it's a samsung t220)

i've noticed a couple of other things too-

the fan doesn't spin normally until it reaches the os; during boot it doesn't spin at all, then spins at 100% for a few seconds then stops again, won't spin again after that until it reaches the os

when the games hang, occassionally vpu recover doesn't kick in and the card just kinda stops, as in the fan stops and the monitor stops getting any signal, but i can still hear music for example. it also does the one-time-100%-spin thing i mentioned above

and tbh i'm not sure if it's artifacting or not, it's like a spike-shaped graphic appears on screen for a split second then disappears every few seconds, i'll try to get a screenshot if it helps

btw is this at all relevant: http://img185.imageshack.us/img185/8059/hardwareaccel.p... ?

thanks again for all the help
May 12, 2010 6:35:14 PM

Ive also had that weird problem with the fan, its normal don't worry...

Something is very wrong on the software side of your card if it drops out of games randomly and the fan stops spinning...

RMA it just to be on the safe side
May 27, 2010 12:27:09 PM

looks like downclocking it by 100mhz for both memory and gpu clock has made the pixels disappear, it's also gone from instantly failing the CCC clock test (with default clocks) to passing it

hoping this is a permanent fix
!