Crossfired 4890s and overclocking

[jeffmoorehouse]

i recently built a new system from the ground up... i am running 2 hd 4890s on windows 7 on this system in crossfire.. i ran the auto config in the overdrive section of CCC but running game after that crashes my system.. my question is, is auto config safe and is there anything i should do to my system before i try to overclock my cards?? i want to get the best performance out of these that i can. still pretty new to all this. pls help

 

[sayantan]

use manual overclocking...increase the clock rates by 2mhz in one step...I use a sapphire hd 4890 and my custom stable clock speeds are:core-860Mhz ,memory-965Mhz... increase the memory and core clock speeds one by one and run stability test each time(use 3d mark vantage gpu)...

 

[Dougx1317]

The highest you could overclock your card is 860/965Mhz? That sounds like a really bad 4890. The memory should run faster than that at stock.

 

[sayantan]

oops sorry ,memory frequency is 985Mhz...

 

[jay2tall]

The auto tune utility doesn't usually work to well. Cards in Crossfire tend to get MUCH hotter than a single card, especially the top card. Watch your temps. This is probably a big factor in your limited overclock.

The auto config is safe, but I have never had any luck with it. The best way is to do it manually and bump up your clocks until it isn't stable, and then back them off 5Mhz or so. Try your GPU first to get your stable clock and then try your memory clock. Just ease it up 5MHz at a time and test.