Need to be careful with GTL voltages, but generally if you're failing Prime or Orthos right away, GTL can help with that and you don't need to apply additional VCore. There's alot of threads out there on it but I found this post to be a good point of reference as it did increase my stability VS what I was "trying" to get done:
http://www.xtremesystems.org/forums/...91#post2716991

Anyway, I've noticed that I've got a good amount of VDroop going on here. .04 max between load and idle. I know that doesn't sound huge, but typically I can see my volts trail off just before orthos fails. Think the mod from johnny bravo would help out in my case? I may be able to minimize the VCore required to hit 4ghz by doing that, maybe I'm just a little nervous about degradation on these chips.... They haven't been out that long yet and I'd rather not kill this one so early on.