Had an interesting problem and a successful sledgehammer solution so I thought I’d share. In trying to normalize my uneven tri-sli (2 EVGA SC, 1 EVGA standard) at a common boost clock, I discovered that my primary card had actually stopped returning to its base clock and utilization was no longer reporting correctly in GPU-Z or in EVGA Precision. The problem persisted through a reboot and any combination of both driver (adaptive vs perf) and OC settings (linked, unlinked etc)
The fan was getting annoying so I decided to wing it and install the beta drivers. Poof, like magic, the 314.21 beta installed perfectly (Windows 8 64 bit) and returned everything to normal. As a bonus, the 3rd card now responds as expected to the offset and all 3 cards are running well at 1100Mhz boost. I also noticed that they are cycling way down to 324Mhz sitting in the GUI as well whereas under 314.09 they would only cycle down to the base clock.
Don’t know if this was unique to my configuration and if something had gone wrong along the way (seems unlikely since this was a new, clean, Windows 8 install), but figured in case someone else ran into something similar they’d know they weren’t crazy!