07-18-2017, 04:29 AM
http://www.gamersnexus.net/guides/2990-v...erformance
Quote:The trouble with this solution is that it is imperfect by nature. First, every chip is not made the same; ours may undervolt better or worse than others out there, and that means there’s no easy “use these numbers” method. You’ll ultimately have to guess and check at stability to find the numbers that work, which means more work is involved in getting this solution to be rock-steady. That’s not to say it’s difficult work, but it’s certainly not as easy as plugging a card in and using it. We found that some games required 1120mv to remain stable, while others were fine at 1090mv. Ideally, you’d make a profile for each application – but that’s a bit annoying, and becomes difficult to maintain. The next option would be to choose the lowest stable voltage for all applications (in our case, that might be 1120mv). You lose some of the efficiency argument when doing this, as the bottom-end is cut off, but still gain overall.
A straight +50% overpower configuration is a huge waste of power down the PCIe cables, which results in running hotter than necessary and thereby louder.
Software is also buggy and frustrating. No, not everyone sees the same issues – that’s the nature of buggy software. It is difficult to precisely pinpoint the issue causing HBM2’s brutal downclocking of -445MHz, but we have seen it happen routinely and on multiple systems with multiple environments. We think that this has to do with manually configuring all 7 DPM states and their corresponding voltage states; when we only configured DPMs 4-7, the downclocking issue did not occur. Fan speed curves are also inaccurate, and report about 200RPM higher than what the user requests. Wattool has the same bugs as WattMan, and Afterburner can’t adjust voltage (yet). The point isn’t to say that it’s impossible to undervolt like we did, it’s just to say that you should really be aware of all the different variables when tweaking. It’s possible to inadvertently hinder performance (in major ways) if HBM2 underclocks without the user’s knowledge. Keep an eye on it.
As for the task at hand, it seems the best possible configuration is to overpower the core (+50%), undervolt the core (roughly -110 to -90mv), and run a fan RPM that keeps temperatures at or below 80C. That’ll depend on your cooling solution, case, and case/room ambient temperatures.
This yields a decent boost to application performance (professional and gaming) without costing the insane +90W draw of a straight +50% overpower configuration.