Vega12 begins to show up in AMD's Linux drivers

Humbug · March 24, 2018

1 hour ago, TheRandomness said:

I'd love to see say, a 5120 shader Vega card. Sure, it might put our more heat than a thermonuclear bomb, but it'd be awesome.

It would not necessarily be hot or power hungry.

The reason vega64 is power hungry is not because of the shader count. It's cause of the clock speed and corresponding voltages. Basically when AMD was finalizing the product they wanted stock performance to be at least on par with the gtx 1080. In order to achieve that they had to set the clocks and voltages way outside the optimal efficient range for this architecture.

An alternative way to achieve better performance is to go wide. More CUs rather than higher clocks. However unlike clockspeeds this is not something that can be tweaked at the last moment based on how Nvidia is performing.

So the hypothetical question would be why didn't AMD plan an even bigger Vega in order to take out the 1080ti while being clocked inside a lower more efficient range? Why does vega64 only have the same number of CUs as the Fury X?

The reason is that AMD has identified that there is an inherent bottleneck in their gcn 1.2 architecture which means that performance gains will be minimal even if they go bigger. So they stopped at 64 x CUs. There were some interesting benchmarks run by gamersnexus which showed that Vega56 performs almost exactly the same as Vega64 clock for clock. This would indicate that even at this level things are starting to plateau and we have diminishing returns. I.e. there is something else limiting performance.

AMD may compete great in the mid-range with rx 570 and rx580 etc or at most Vega56. But until AMD can sort out that bottleneck they will not beat Nvidia's absolute top end parts.

Don't expect this high end bottleneck to be broken with anything based on Vega. The first real shot will be Navi, cause Navi uses a totally different method to go wide and create big powerful GPUs, and btw it also gets around the requirement of having to clock each chip too high so that should allow a leap forward in efficiency for AMD. I am not saying Navi will be be great, it could be awesome or it could suck... but on paper it is the next realistic shot at taking out the Nvidia high end, not Vega 7nm.