I picked up a used Sapphire OC 950 today. The price was right, and I wasn't entirely happy with my Gigabyte 7950 900 MHz WF3.
My old Gigabyte ran 1.09V stock, maxed around 1000 at that voltage and managed 1100 with about 1.14. More volts got a bit more out of it, but it wouldn't quite do 1200 at any voltage. Even watercooled....I dropped my GPU temps from near 70C to 38C load and that card gained exactly nada in the OC department (67% ASIC) The memory also sucked with 1400 MHz the limit.
So while it was a very capable card...when I had the opportunity to buy the Sapphire for the same or even slightly less money than what I'm flipping the Gigabyte for...I went for it. Card still has 7 months of warranty on it so a pretty safe bet anyway.
The Sapphire has 90.4% ASIC quality, but OK that doesn't say much. Defaults a full 0.1V lower than the Gigabyte though at 0.993.
The actual load voltage according to GPU-z is 0.98. With the stock cooler (+ the Gigabyte WF3 fans actually...because the Double X cover with fans doesn't quite fit my case. So I strapped the WF3 fans to it) it's running mid 60C load. VRMs ditto.
Without touching the voltage the card would run 3Dmark and Heaven at 1075 MHz which I found extremely impressive. At 1.00V actual (1.025 set) it runs at 1100 core all day long. I pushed onwards a bit but soon needed to put silly fan speeds on it to keep it within acceptable temps.
It actually runs 1200 core at
1.10V and memory 1700 at 1.65. I didn't test the memory too much but performance kept going up until I set it to 1800 where it locked up in 3Dmark.
After that it gets quite difficult very quickly. I don't like seeing over 85C VRM temp but they're impossible to keep cool with this cooler (has the stock heatsink on the VRM's but I am wondering if it's not doing more bad than good)
I even benched 1250 MHz at 1.111V actual. But any further than that was a no go. 1275 would start artifacting a little while into the tests...and going over 1.13V seemed to do absolutely nothing except overheat the core and VRM's even further. VRM's race towards 100C and the core is 80+ at this point.
Time to go back to water I think. It might well be that this card will never do more than 1250 regardless but it's the voltages that amaze me. And in any case, 1200/1250 is nothing to sniff at. I suspect that putting a WB on the core (I have an EKWB universal block) will drop VRM temps all by itself, hopefully putting a quiet fan and better heatsinks on them will keep them in the 70-80 range.
Will take a few weeks though because I had to order a new fitting for the block.
Some screenshots below...don't look at the actual 3D scores too much because I didn't bother rebooting between runs, just changing the clocks and that tends to score quite poorly vs rebooting every time. I was doing stability checks more than anything so wasn't worried about the score.
I wish I could have this card with the Gigabyte's VRM system...ran way, way cooler than the ones on the Sapphire card even though they had NO heatsinks on them.
Edited by JCviggen - 12/11/12 at 10:51am
