Everyone talks game about how they don’t care about power consumption. We took that comment to the extreme, using a registry hack to give Vega 56 enough extra power to kill the card, if we wanted, and a Floe 360mm CLC to keep temperatures low enough that GPU diode reporting inaccuracies emerge. “I don’t care about power consumption, I just want performance” is now met with that – 100% more power and an overclock to 1742MHz core. We've got room to do 200% power, but things would start popping at that point. The Vega 56 Hybrid mod is our most modded version of the Hybrid series to date, and leverages powerplay table registry changes to provide that additional power headroom. This is an alternative to BIOS flashing, which is limited to signed drivers (like V64 on V56, though we had issues flashing V64L onto V56). Last we attempted it, a modified BIOS did not work. Powerplay tables do, though, and mean that we can modify power target to surpass V56’s artificial power limitation.
The limitation on power provisioned to the V56 core is, we believe, fully to prevent V56 from too easily outmatching V64 in performance. The card’s BIOS won’t allow greater than 300-308W down the PCIe cables natively, even though official BIOS versions for V64 cards can support 350~360W. The VRM itself easily sustains 360W, and we’ve tested it as handling 406W without a FET popping. 400W is probably pushing what’s reasonable, but to limit V56 to ~300W, when an additional 60W is fully within the capabilities of the VRM & GPU, is a means to cap V56 performance to a point of not competing with V64.
We fixed that.
AMD’s CU scaling has never been that impacting to performance – clock speed closes most gaps with AMD hardware. Even without the extra shaders of V64, we can outperform V64’s stock performance, and we’ll soon find out how we do versus V64’s overclocked performance. That’ll have to wait until after PAX, but it’s something we’re hoping to further study.