I recently received a couple more 670's for batch testing. Here are my results.
All three chips are from batch #L937B909 Malaysia.
Chip1 cb @ -141c, cbb @ -120c, wprime32 @
6141MHz, Spi 1M @
6168MHz
Conclusion: cb does not allow cold enough passes to get good scores, great wprime chip, poor spi and pifast chip.
Chip2 cb @ -167c, cbb @ -130c, wprime32 @ 6050 (no result worth posting), Spi 1M @
6363MHz
Conclusion: good temp headroom, way better spi and pifast runs but poorer wprime.
Chip3 cb @ -153c, cbb @ -110c, wprime32@ 6120 (no result worth posting), Spi 1M @
6437MHz
Conclusion: although temp headroom was not as good, better oc for spi and pifast runs.
Tests were obviously on LN2 with a single stock cooled gtx260-216 in slot 1.
Shammy settings with latest bios on classy p55-200 board. All vcore was limited to 1.9V max as not to harm the chips.
The best tidbit I have for anyone preparing to bench these chips, they scale with cold, not voltage, if you overvolt them you WILL lose them.
Thanks to my suppliers for the opportunity to test the great variations within the same batch. The chip game is as hit and miss as ever.