How to play HD w/out affecting speed?

[los]

ok. thanks again guys

[pauldacheez]

Lock Threads to Cores doesn't even do anything on OS X, last I checked; threads still go to all four logical cores on my dual-core with hyperthreading (i5-2557M in a MacBook Air). You can disable hyperthreading entirely (in Instruments's preferences if you have Xcode installed) to do nearly the same thing, but it actually gives me a slight slowdown (likely from other processes having to wait to use the same cores – not a problem on quad-cores since Dolphin can only use two or three of them).