Received my 2 Sapphire 4GB yesterday, flashed both to 8GB right away. Notice 16.7.1 WattMan undervolt is buggy, especially if RX480 is not on the first slot. I can't get it to undervolt. Both card seem to be stable at 2250MHz max memory so far. Afterburner 4.30 beta 4 does not support any adjustment yet.
Open bench Z87-plus + g3220, EVGA 850GQ, measure using Kill-a-Watt
Using iGPU Idle, no RX480: 27W
1 x RX480 Idle: 58W in Windows before driver installation
1 x RX480 idle: 45W in Windows after driver 16.7.1
1 x RX480 Claymore: 950/2250, 900mv, 165W , 25MH/s
1 x RX480 Ethminer + Ethproxy: 950/2250, 900mv, 20MH/s.
On this board, if iGPU Multi-Monitor is enabled, it *may* be possible to boot in headless mode but most of the time it does not work. So I put a non-ref 7950 as the main boot device so I can boot without connected to a monitor.
The RX480 does work on a non-UEFI mainboard, Asus P6T SE. This one always boot fine in headless mode.
7970 on 16.7.1 (tried 15.12, 16.2.1 same result), Claymore: 18.3MH/s sent rate, Ethminer + Proxy sent rate 20.3MH/s. 7950 on Claymore: 17MH/s. It seems Claymore is slower than Ethminer on Tahiti and I have to mix it with RX480. I am not dual mining on Claymore.
WattMan undervolt bug:
With just 1 GPU installed, RX480, test on both the Z87 and X99 board, undervolt setting seem to be wiped out after restart (By wiped out, I mean it shows 900mv but it's at 1.15v.). I tried to set the setting in only Global setting, as well as Global + 3DMark profile + Claymore exe profile, same result.
In order for setting to stick by verifying the VCore using GPU-Z, I have to set Global profile to my preferred setting like 1075mv for example, check in GPU-z and it's running at 1.15v, go back to set voltage back to Auto in Wattman, start 3DMark, then go back to set voltage to 1075mv, verifiy in GPU-z that's it really running 1075mv vcore. Then start Claymore and got this.
When Claymore is running, Frequency/Voltage control seem to all show N/A but it's fine if it's 3DMark. The reason why it's running at 1266MHz is because I can't set the Claymore to run at 950MHz individually as I want Global profile to be 1266MHz. Also, if I adjust the frequency of the Global profile after the 1075mv vcore is finally sticking, I seem to lose the undervolt right away, and I have to repeat the long procedure again. :sneaky:
The above is 7950 non ref in slot 1, RX480 in slot 5 for now, voltage adjustment by Afterburner for 7950, Wattman on RX480. I absolutely can't seem to find any trick to undervolt in this case, so hopefully Afterburner come to the rescue soon or Wattman get fixed.
The ref RX480 at 2200-2500RPM is very quiet compare to the non-ref 7950/7970 fan at 60%, the MSI 390 Gaming at 50% is noiser than this. Although the ref fan really doesn't have any headroom the moment I try to increase the power limit slider.