Overclocking 670 - memory settings weirdness

[andybird123]

So now I've got my 670's on water I thought I'd have more of a play with overclocks... got my GPU offsets dialled in quite nicely and went after memory... got to +400 on one card and +500 resulted in artefacts so backed off... then went to Heaven to run a benchmark to check scores were increasing vs. +200 and then noticed that in both precision X and GPU-Z the memory clock would start at 1800 but then after a few seconds would shoot back to 1502

having played around a bit more I've found that both cards do it at any setting... even weirder as I have one Superclocked card which by default should be at 1550 anyway, and even it seems to be going to 1600/1700 fine but then reverts to 1502 after a few seconds - if I swap back and forth between card 1 and 2 in GPU-Z it reads correct for a split second then reads at 1502 again

anyone else come across anything similar?

 

[andybird123]

never mind, loaded 1.21v bios back on and everything is back to normal (and getting better scores in heaven to boot)... guess I must have not saved my old bios properly which is a bit of a worry if I have to RMA either of these at some point!