Once Stable OC Always stable?

I used to have my q6600 overclocked to 3.4ghz (5 months ago) and it was stable at that speed and also at 3ghz. However after a particular error my mobo (p5k-e wifi/ap) said overclock failed! revert to default settings? I thought this was because of my overclock and i just clicked yes and went back down to 2.4ghz. I know realise that this may not have been the case and i have re-overclocked my cpu back up to 3.0ghz because this is as far as i really need it to go. My question is do i need to go through a stress test again or is it not necessary?

Also i recently realised i had my cooler mounted in the wrong direction, i fool enough not to realise the fan blows over the heatsink no tthe other way round:angst: ....

So now after overclocking to 3ghz speedfan shows idle cpu temp of 31 C and core temps of 40 40 34 34.
This is at 100% fan speed but i want to turn it down to about 70% are these temps to high?

temps are fine

Thanks about the temps but what about the stress test should i redo it?

I think after a reset of the OC'd settings it'll be worthwhile to run a quick test to see if it is stable.

Something like:
SP2004/Orthos
3DMark06 on a loop

Ok then hummpph extraness lol ah well guess its got to be done then thanks for your help guys