HD4850 - overclocking issue

[D749]

Threw in one of my two HD4850s tonight and ran a battery of tests while at stock (3DMark Vantage, FurMark, Lightsmark, etc.). I then cranked the card up to 700/1000 and re-ran the tests. No problems. Later I got adventurous and cranked the memory up to 1100 which was a bit too high (e.g., driver crash then black screen while running FurMark). A reboot got me back into Vista but for some reason I can't seem to get back to 700/1000 without having the driver crash (e.g., while running FurMark). I'm not sure why a previously stable clock would now be so unstable.

Any ideas why this would be? Could I have damaged the card somehow or missed a setting in CCC?

Thanks.

[xMrBunglex]

i doubt you damaged the card if you didn't do any volt mods. is your ambient temperature warmer now? that's the only thing i can think of.

[ghost101]

eas why this would be? Could I have damaged the card somehow or missed a setting in CCC?

Thanks.

It was probably never stable in the first place. I doubt temperature is an issue unless its running at 106C+.

[jimmyz]

I had issues with various settings just drop the memory down to 1050 or so (try to keep steps at 25mhz ). my card wouldn't complete a run at 780 for example but liked 900...go figure, same voltage BTW. I had my voltage set for my 900 runs and was experimenting to find a nice cooler gaming speed. also my ram did fine with 1150 but didn't like 1125.

[omega1alpha]

I could barely overclock these cards with the stock cooler. I'm sure a better cooler would help. So, I'm not shocked that you're having issues with overclocking. Try and get a better cooler.

[jimmyz]

I could barely overclock these cards with the stock cooler. I'm sure a better cooler would help. So, I'm not shocked that you're having issues with overclocking. Try and get a better cooler.

for a quick fix use an 80mm fan and some rubber bands put the fan over the round intake hole. and secure with the bands, drops temps a bunch.

[D749]

for a quick fix use an 80mm fan and some rubber bands put the fan over the round intake hole. and secure with the bands, drops temps a bunch.

Haha - I love it! I'm keeping my eye on the new Thermalright VGA cooler. The only problem is going to be fitting it. With the P182 and a card in the lower slot room becomes tight.