I hang out on the eVGA forums as well, and a lot of us ordered the Classified cards around the same time. As the cards started coming in, it was apparent that the default voltages were all different, some were as low as 1.013v and as high as 1.050v. I found that a little odd because the reviews I read on the card reported the voltage as being 1.025v default.
I was happy when my card arrived and it's vtt was 1.025v Within the hour I pushed the core slider in Precision to 900mhz without touching the voltage, and played BF3 for the rest of the night. After I saw the "560Ti OC" thread on these forums the next day, I wanted to get a 3dmark11 score to compare to theirs, so I ran the benchmark at 950mhz core, 1.025v.... and it hard locked. After rebooting, I checked my 950Mhz overclock in OC Scanner and it quickly started picking up artifacts. I used EVTuner to to bump the voltage up one notch, which was 1.038v, and then scanned for artifacts again(there were none).
Feeling confident, I went ahead and ran 3dmark 11 again without a hitch, and I've been playing BF3 and Crysis 2 on this overclock setting, I think the 448 core cards are great.
i7 6700K - Corsair AX1200i - Asus ROG Maximus VIII Gene - Corsair Vengeance DDR4-3000 - XFX Radeon Fury X Crossfire - LG 34UC97 Cineview Curved UltraWide - http://www.3dmark.com/fs/8133076