A couple of weeks back, I picked up a PowerColor Red Dragon Vega 56 because I wanted to see how a Vega 56 would do with the fabled Samsung HBM, improved cooling, and a Vega 64 BIOS. Additionally, this along with the XFX Vega 56 Double Dissipation are the only Vega cards I'm aware of with after-market, "open" style coolers that only take up two PCI-e slots. All the others I've see are triple slot. The only reason why I went with Red Dragon over Double Dissipation was because it was the first and cheapest one I found with Samsung HBM.
First, let's start with some baseline benchmark results. These results are with the stock Red Dragon Vega 56 BIOS and native macOS drivers and power tables.:
Of course, the first thing I did after receiving the video card was to take it apart and apply some Liquid Metal. With the liquid metal, temps have never even reached 70C. The cooler does an amazing job at cooling the card and, even with the fans cranked up, the noise is never offensive or annoying. At stock settings, the fan is inaudible to me even when the card is under load and, at idle, the fans don't spin.
To extract better performance from the card, I flashed the BIOS with the Sapphire Nitro + Vega 64 firmware. Since all Vega cards have dual BIOS, I left one setting at the stock Red Dragon firmware and can switch back within seconds.
Secondly, I used VGTab to undervolt the GPU voltage from a stock of 1200mV to 1050mV. I left the GPU clocks at the stock Nitro + setting of 1630MHz and overclocked the HBM to 1050MHz. I also cranked the fans up to about 75%. Temps topped out at 65C with these settings. I'm pretty sure I could push both the GPU and HBM clocks a bit higher but I just got too sleepy to do anymore testing...
Here are the results:
As you can see, the improvements in performance are quite substantial and was achieved very easily. Again, I'm very confident there's still more headroom for even more performance. However, the gains in performance come at a cost... Power consumption and heat.
With the above settings, total system draw peaked at a whopping 481W!! With the default Vega 56 BIOS and default power tables, I observed total system draw of 343W. Total system power draw when the system is idle is ~100W.
While the liquid metal and heatsink do a fantastic job of cooling the card, the card itself nonetheless generates a considerable amount of heat and, by nature, the the "open" style cooler keeps the heat inside the case rather than blowing it out the rear of the system. This, in turn, causes other components in the system to get hot. There was enough heat trapped inside the case to cause the motherboard VRM to overheat and eventually the entire system would shutdown. (*Note: I did my initial testing on a very warm summer day and ambient temps were right at 28C.)
To combat this, I had two options, (1) open the side panel which is impractical and would turn in to a royal PITA really fast or (2) increase the case fans enough so that the hot air is evacuated from the case before it can cause any problems. For me, this meant setting case fans to 50% at idle. At 50%, I have to go out of my way and put my ear an inch or two from the case before I can hear them. With this setting, CPU temps are also lowered.
So, the moral of the story is, the Vega cards have a ton of potential. All we have to do is keep everything cool enough. Squeezing lots of performance out of a Vega can and will increase power consumption dramatically.
Just for kicks, I wanted to see what would happen if I opened up the case and pointed a desk fan at the system...
Update:
1640MHz core clock. 1070mV. 1075HBM. 50C Target Temp. 2400rpm idle fan. 4900rpm max fan.