Montblanc reacted to a post in a topic: nVIDIA Updates Web Drivers for 10.8.4 (313.01.02f01)
Hi, I had a similar problem with a Vaio laptop. Stuck at grey screen on battery but loaded fine on mains. If I booted on mains then switched to battery everything continued to work OK. Setting cpus=1 in the com.apple.boot .plist worked and when I'm running on mains typing cpus=2 at boot gave me both cores. Must be an issue with one of the power management kexts but I can't seem to fine which one(s). Hope this helps.