Radeon 7970 is nice in terms of performance but it comes at a price in terms of fan noise. These videocards consume a lot of power (8+6 pin 12V connectors) and emit a lot of heat when under full load. Small fast turning fans are noisy. Reference design calls for one 80mm radial fan like HIS H797F3GM. It can move a lot of air but is extremely noisy. There are also designs with 3 80mm or 92mm fans like Gigabyte GV-R7970C-3GD. It should be noted that Gigabyte model is also factory overclocked to 1000 Mhz (compared to 925 Mhz standard)
I had a pair of each cards and tried running them both and I wasn’t happy with either of the cards under sustained load. They ran hot and noisy. Here are some measurements to compare. I measured the noise with iPad app 1 foot away from the desktop. I used S.T.A.L.K.E.R. Call of Pripyat to generate 100% crossfire GPU load (2560×1440, everything maxed out and looking at a lot of grass). GPU data was captured by GPU-Z. I only measured data for the 1st GPU. Generally, second GPU in CrossfireX config tends to run 10..15°C cooler than the first so if I could get cooling of the first GPU under control, second should be no problem. I did separate test with and without case side panel installed because mine doesn’t have any means of ventilation. Two fully loaded 7900 generation videocards generate a lot of heat that starts to build up. Most likely I’ll need to come up with some kind of side panel fan.
|Configuration||Temperature||Fan speed||Noise Level|
|Computer is off||N/A||N/A||35dB|
|Gigabyte 7970 idle. Side panel irrelevant||48°C||40% – 2200 RPM||43dB (pretty quiet)|
|Gigabyte 7970 full load. Side panel closed||87°C||100% – 3850 RPM||57dB (loud)|
|Gigabyte 7970 full load. Side panel open||80°C||100% – 3850 RPM||60dB (even louder)|
|HIS 7970 idle. Side panel closed||63°C||29% – 1500 RPM||42dB (ok)|
|HIS 7970 idle. Side panel open||51°C||20% – 1100 RPM||40dB (ok)|
|HIS 7970 full load. Side panel closed||90°C||55% – 3300 RPM||55dB (unpleasant)|
|HIS 7970 full load. Side panel open||85°C||55% – 3300 RPM||60dB (too loud)|
|HIS 7970 manual 100% fan. Panel open||N/A||100% – 5150 RPM||73dB (unbearable)|
|HIS 7970 manual 100% fan. Panel closed||N/A||100% – 5150 RPM||70dB (unbearable)|
I considered installing waterblock and the rest of the watercooling system and decided against it. Even though I have enough space in my LIAN-LI case to fit everything inside (even radiators), it would make swapping out parts too much hastle. And then there is always risk of a leak, pump failure, etc.
On the air-cooling front, I’m going to try several options:
1) Replacing stock cooler on HIS Radeon HD 7970 with Arctic Cooling Accelero Xtreme 7970. It gets decent reviews in terms of cooling and noise. The downside is that you have to install it yourself and in doing so you are dstroying the thermal pads from the stock cooler. If you would want to get warranty service, you’ll have to find new ones and reinstall everything which can be tricky. In fact as I’m typing this post, one of my HIS 7970 sits in the next room waiting for non-conductive thermal glue to cure on RAM and VRM heatsinks. Hopefully by tonight it will have cured and if I didn’t destroy anything in the process, I will be able to install main heatsink and run some benchmarks. Mean while I tried connecting the fans to 12V PSU (to run on 100% speed) and was quite happy with the noise level. So provided that the card will not overheat, I may stop with this solution and mod the second videocard in my 7970 crossfire config in the same way. I’m keeping my fingers crossed…
2) Replacing 3 stock 80mm fans on Gigabyte 7970 with Noctua 80mm fans. They should move as much if not more air and are near silent even when running full speed. This is a much less intrusive procedure since all it only takes a couple of screws to remove the fans while leaving the heatsink in place (no radiator gluing required). The down side is that I will need to create a custom bracket to keep them permanantly attached to the videocard. I’ll probably have to design it in SketchUp and have shapeways.com fabricate them for me.
If both solutions work, I’m likely to keep Gigabyte cards with Noctua fans. I like Gigabyte cards better because they ramp up fan speed quicker. The way HIS keeps fan at 55% when you can almost boil tea on the videocard is plan wrong. Also Gigabyte comes with factory overclock which is nice. I also like Noctua fans. Every time I build a new PC, first thing I do is replace all fans with Noctua which results in very silent and well cooled PC.
So if I’m lucky, I’ll be able to test the first option tonight and post the results. Stay tuned.