7950 Vapor-X Power Limit problem

[45454asasa]

Just received it today;

After playing some games with stock settings I decided it was time to OC, and went straight to 1100 core clock. Once I started up Furmark I noticed it was varying between 700 and 900? Increasing the power limit to the maximum 120% allowed it to reach ~940MHz tops.

Tried the boost bios and it wont even stay at the 950MHz without increasing the power limit -- it sits at ~675!

Temps are OK, with the +20 limit and boost clock, it sits at 60C/50% fan... although that seems a bit loud and hot to me.

Whats going on???

 

[45454asasa]

Anyone have any ideas?

 

[raghu78]

Anyone have any ideas?

Furmark is a power virus and will definitely throttle clocks. Check clocks in normal apps like Heaven 3,0, 3D Mark 11, BF3, Crysis 2. If it goes below 850 Mhz which is the core clock then its a faulty card. Even with power limit at 0% it should run consistently at 850 Mhz and never go below that. if it works then check again with the boost BIOS. max out power limit to +20% and it should run at 950 mhz without any throttling. Then go for overclocking.

if any problems return to shop for new replacement.

 

[45454asasa]

Well dang am I ever stupid! Thanks!

It wont throttle in anything else I put it under, and is OCing very nicely

I have one more question though -- is ~105C VRM temperature OK?
And also, why might other people with the same card be able to run regular clocks in furmark without throttling but not me? This card seems to OC very well and not throttle in anything outside of that... it just seems weird to me. I dont trust it

 

[SonDa5]

Furmark is a power virus and will definitely throttle clocks.

Never heard that before. I like to use furmark for stability testing when over clocking.

My best over clock runs of benchmarks are furmark stable as well. I run at least 10 minutes. 10 minutes is usually enough time for me to see how good cooling is working and how stable the over clock is.

 

[45454asasa]

Really? Thats on a 7950? Very weird.

Im at 1275/1810 @ 1.162v stable right now. Could go higher, but those damn VRMs throttle the card at 110c. Currently the core tops out at 58c and the VRMs at 104c.

Ill happily take that, considering I only expected about 1150/1500

 

[SonDa5]

Really? Thats on a 7950? Very weird.

Im at 1275/1810 @ 1.162v stable right now. Could go higher, but those damn VRMs throttle the card at 110c. Currently the core tops out at 58c and the VRMs at 104c.

Ill happily take that, considering I only expected about 1150/1500

1275/1810 is a great over clock for that voltage. I think most VRMs are rated to operate at max temps around 125C. I think that is way to hot.

Sounds like you have a very nice card. I would try a different BIOS on it. The Sapphire HD7950 950mhz edition BIOS might work out well for you but I think 1275/1810 stable with the voltage that you have is golden.

One thing I would do for certain with your card is water cool it. Once water cooled your VRM temps will be much cooler with a full cover block or you could look at Swiftech Hyrbrid GPU only water block with a nice big VRM/PCB heat sink.

 

[45454asasa]

I agree. I sure wish I had the money to watercool, but I do not. Got this card for $240 AR thru the newegg ebay 20% deal, which is stellar.

It has just one flaw that drives me crazy... fan grinding! Argh. Of course I'd take that over a poor overclocker, so no way in hell am I RMAing it .

Is it known whether or not the 7970 BIOS' have tighter timings on the memory, or is that just an assumption?

Thanks for the help.




New problem... if I install drivers aside from the default 12.8, I get terrible screen flickering/artifacting on any non reference clock speeds. WTF?

 

[raghu78]

Well dang am I ever stupid! Thanks!

It wont throttle in anything else I put it under, and is OCing very nicely

I have one more question though -- is ~105C VRM temperature OK?
And also, why might other people with the same card be able to run regular clocks in furmark without throttling but not me? This card seems to OC very well and not throttle in anything outside of that... it just seems weird to me. I dont trust it

105c is very high. You should try and keep VRM temps around 90c, max 95c. maybe its better you back off the overclock a bit. Given that you are at 1275 mhz i suggest you back off to 1200 Mhz. its just better in the long term. you don't want to damage the card.