CF290X overclocking help

[Born_2_Kill_83]

So I've been having a play with my Crossfire 290X MSI Gaming's, my maximum stable overclock seems to only be 1100/1400 @ 55mV, anything more on either core or memory I start getting a little screen flicker or perhaps the odd artifact.
I’ve seen other people pulling more than this with these cards, could it be I’m limited down due to running them in Crossfire?

Second thing is the temps, they appear to be fine at stock settings both in-game and benching but with the above overclock they hit 94c in 5 mins of benching and start throttling down, anything I can do to stop this? Again I suspect the problem might arise from Crossfire again, can any-one confirm. They seem to run hot for none reference cards.

 

[4737Joker]

Non ref cards dump the heat in to the case, you probably just need better airflow.

Those clocks are not bad for +50mv, people normally pump more v through them for higher clocks.

 

[eyetrip]

For temps, there may be nothing you can do other than to buy another case. What case do you have now?

I was running my stuff in a Carbide 300R, and no matter how many fan spaces I filled and no matter what orientation, I struggled to get that top card to stay under 80. This is with two powercolor PCS+ 290's

I then upgraded my case to a Panteks Enthoo Primo, and it's easy keeping that top card around low 70's running up to about 1100, though I can do that on +0mV on my cards - after 1100, they quickly start to require more voltage though.

+100mV will get me to around 1175. Playing with Sapphire Trixx, I seem to only be able to up the voltage to +155mV, but with that can only get up to 1225 (I think - didn't try very hard here). If I go to around +175mV in Trixx I start to get black screens.

 

[Born_2_Kill_83]

My case is a saw subject, I bought H440...cause it looked good , I now have 6 120mm fans pulling air into the case and one 140mm pulling air out but it still isnt enough when their enclosed by covers.

I'll have to try it without he side panel on and see what happens, I'd never be able to use anywhere near 100mV due to temps nevermind over it with the covers on.

 

[4737Joker]

Take the brackets off the empty pci slots on the case, not too familiar with the case but can you not turn some of the fans around so the suck air out of the case? top mounted fans for example.

 

[Born_2_Kill_83]

Can do but this then starves the CPU (Noctua) of air then

 

[4737Joker]

It shouldn't do if you have front intakes, looking at the pics of the case theres plenty of open space between the front intakes and the where the cpu cooler will be mounted so cool air should get to it easily.

Having the top fans blowing the hot air back down in to the case can't be helping things, it needs somewhere to go, as you have high static pressure i'd take the pci brackets off first and see if that helps (its not going to suddenly drop 10c of temps like). If not turn those fans around, your going to have to play around a bit to see what works best for you.