4890 Potential Memory Issue?

[Ritsugamesh]

Hi guys,

Had my 4890 for little over a year now, never failed me and has ran like a dream.

I've dabbled in o/cing it from time to time, never any voltage modification though. (I just can't help wanting that bit more bang for my buck!)

I had left it at defaults of 850/975 core/mem respectively for quite some time, though after wanting to coax it a little more when playing BF2 at 1920x1200 I finally decided to find the card's max stable overclock and keep it indefinitely.

I'm noticing a strange screen flicker whenever I watch something like a youtube video, etc yet in gaming it seems ok. This issue I have isolated to the memory as I can o/c the core to 950 without difficulty, yet even a 5mhz change on the memory causes this flicker without fail. The overclock that I had furmark stable was 950/1100.

It most definitely did not used to do this, should I be worried about o/cing the card with this potential issue? Looks like it may have to remain vanilla stock afterall!

Cheers for any help you can provide.

 

[Jayce85]

What cooling are you using? I own several XFX HD4890s none of they came with cooling on the VRAM.
I've used a number of coolers in both single and crossfire setups; but as yours is a single, lets stick to that.
i've managed 970 GPU and 1200 VRAM with Arctic Cooling Twin Turbo Pro, but it doesn't hold up under load.
Furmark is not a stress test!
It will give you some idea how good your cooling is though. Running Futuremarks benchmarks will give it a tougher time, though I found the best stress to be running Crysis benchmark through a number of resolutions and max settings.

Get some cooling on your VRAM, and perhaps lower the GPU core by 10MHz from Max, to give a bit more stability.

 

[Ritsugamesh]

Thanks for the reply mate, the cooling I am using as the stock shroud cooler as can be seen here:

The problem is not that I can't manage the overclock, as I have it stable whilst gaming as far as I can tell. The issue lies in the strange screen flickering I am receiving when the memory is overclocked. I will put a bit more cooling onto that and get back to you with how it turns out!

Thanks for the help mate, I will start using the Crysis benchmark too.

 

[Tealc]

Set up a 2D profile and a 3D profile with Ati Tray Tools and have it Autooverclock. You'll get a flicker when switching between modes but should remain stable throughout 2D operation. You can set 2D clocks low as well (240/250 or less) and reduce heat production and power usage while at desktop or idle. This is how I have mine set. A 14 degree idle reduction and a 40Watt power saving.

HD4890s flicker when the GDDR5 speed is adjusted so I can only assume that for some reason even though you have set the speed with some tool it is throttling or adjusting when you view certain things.

 

[mmj_uk]

4xxx series had a lot of bugs when overclocking the memory which caused flickering, I think (not sure) that some AIB partners released updated BIOS's to rectify it but if you can't find one then it's best to just leave the memory alone.

EDIT: There's a thread here about it from last year but I can't seem to find any bios update:
http://forums.overclockers.co.uk/showthread.php?p=14103933

 

[Ritsugamesh]

Absolutely cannot thank you enough for the help guys!

Tealc, Ati Tray Tools is a godsend! Got my gpu underclocked to 240/500 with an undervolt of 0.925. Saving on power and lowering my temps across the board.

As soon as 3D kicks in I get my 950/1100 overclock rock solid stable. One slight annoyance is the forced use of the fan profiles within ATT rather than allowing CCC to handle that, although it is only a very minor niggle!

Interesting thread there mmj, I noticed some people were considering an RMA process. If this becomes a big issue I may consider, I believe my Asus card has a 3 year warranty.

As a final question, does anybody know if Asus provide warranty after overclocking a card? I would assume so considering they package an overclocking utility (smartdoctor) with the gpu but you never can know.

Once again, thanks for the help guys.