Sounds like youre running 170w 100% board power target, but sliding the slider up to 133% (1.33 x 170w = 226w) is doing nothing. Doesnt really do anything on mine either, not sure if it even works. What does work is re-targetting your 100% board power to 225w. The reason overclocking your ram makes the core throttle is almost certainly because ram draws a bit of power - going from +0 to +900 on mine adds another 10% TDP to the power draw and I was pulling close to 270w per card at that time which means the mem OC was pulling another 27w or so.
What bios are you running, a stock EVGA 670 vanilla bios? Can you upload it?
As for flashing FTW etc onto your card, depends, 4gb bios to 2gb card not advisable. 2gb to 2gn card of same brand probably OK. No guarantees though. Cross flashing different manuafacturers bios onto cards is where you can really run into trouble and brick your card, but other times it works out. Its always best to mod your own cards bios though.
edit - hang on. 100% board power for a 670 is 140w........so 122% slider *would* be in theory 170w which isnt much (its stock target for a 680). Might need to adjust both 100% board power and max board power targets. How strong is the reference 670 VRM? I wouldnt think too strong based on nvidias designs in the past.
Here, try this.Vanilla EVGA 670 modded to 200w 100% board power and 225w max board power. Leave your power slider at 100% and see if its any better. Clocks are stock with boost limit rasied to 1359 so it should hit that now without overclocking in software, fan is 20% min 100% max. voltage is 1.212v. Use this at your own risk of course, its pushing more than your card was made to do.
BIOS REMOVED THINK THE FILE BEING 96KB WAS NO GOOD
edit 2 - change file type from text back to .rom and open with a program (KGB bios editor, etc to verify its ok before flashing. I changed it back and forth a couple times on my pc and its fine, just cant upload roms here).
Edited by CryptiK - 2/2/13 at 1:28am