Originally Posted by Currency Lad
GPU Boost 3.0 (and presumably the new GPU Boost 4.0 for the 20 series) works much better than GPU Boost 2.0 under Kepler. It's been a while since I had my 780s so perhaps GPU Boost 2.0 works better with the latest drivers - I don't know.
But back in the day, GPU Boost 2.0 was an absolute pain to get a high stable overclock with - that's why there was an advantage to disabling it. Skyn3t's BIOSes (they were tailored for each card) allowed you to run at your highest stable overclock all the time provided you had the headroom. I forgot to mention they also unlocked the voltage to a maximum 1.212V (up from nVIdia's default 1.168V). Unfortunately, Kepler was the last generation that could be successfully edited at the low level that skyn3t did it.
If I recall correctly, I was able to get a stable overclock of 1350MHz on the core and 7200MHz on the memory with my cards using skyn3t's BIOS. Other people couldn't achieve better than say 1200MHz on the core and 6500MHz on the memory, so your mileage may vary. The silicone lottery still applies.
I recall people posting similar problems with Kepler BIOS Tweaker not applying the set voltages correctly as you mentioned and also recall problems with the power tables. You might want to research some of the earliest posts in this thread for information (just do a search for KBT within the thread).
If you're interested, all the info and links to skyn3t's BIOSes are on the first page of this thread. Just proceed with caution and use common sense. Backup your own BIOS first in case something goes wrong (use NVFlash - GPUZ doesn't always backup correctly). Then you can always reflash back provided you have access to another GPU (any one will do) and a 2nd PCIE slot on your motherboard.
Don't do the LLC mod (it was discovered later to cause instability) and don't up the voltage beyond 1.3V unless you have extreme cooling, especially on the VRMs. On air you don't want to go above 1.212V.
Be sure to read OccamRazor's guide on the first page and also check out some of his posts. He was super super helpful to many users back in the day.
Have a good one!
Thanks for the info. My GTX 780 in my "Retro Computer" today is the EVGA GTX 780 Classified version and is supposed to be one of 3 cards in the 780 line (the others being MSI Lightning and The K|NGP|N) that are supposed to allow unlimited voltage control well beyond 1.212v. And in fact in the beginning I had mine running at 1.287v under a custom bios I tuned myself with Kepler Bios Tweaker just fine. I don't know exactly what happened but then later in the same computer I saw it was only running 1.208v suddenly. And now I can't get it to go any higher than 1.208v no matter what I do. If I had an EEVBOT I could probably push it further but sadly they're Unobtanium. I'm still leery about using any other bios and I currently have the card stable @ 1267 Mhz even with 1.208v max, so I'm happy enough with it as is. And that's with full boost table enabled with multiple steps and letting the card boost up/down all over the place as it needs to, which also leads to nice power consumption. I got lucky and got a card with 84% ASIC Quality used off ebay. And it's air cooled with the (admittedly huge) factory air cooler from EVGA and perfectly fine. Maxes out 75c in gaming, 84c in benchmarks, but that might be the crappy small case I have it in and might be improved in a bigger case later. My only complaint is back when I had the voltage successfully running at 1.287v with my kepler-bios-tweaker-tuned-stock-bios on it, it would run 7804 Mhz ram perfectly stable all day, I have benchmark results from it running that ram clock and everything. But now down at 1.208v I had to drop it down to 7220 Mhz ram speed for stability. I'm still not sure what exactly happened there. Maybe the card's degrading, but I doubt that. EVGA Classified cards are designed to run high OC 24-7 for years.