lower GFlops in IBT is 2 fold.
1. Hyperthreading does have a negative impact... The real cores are overloaded and can't handle all the instructions.
2. Like this guy, he only tested with 1024MB ram. You have to test _ALL_ memory in order to get highest performance AND truly test stability.
We've been over this before Sonda!!!
Other things I have noticed that affect GFLops in IBT.
Dual channel memory vs single channel (about 10 GFlops for me)
Ram speed, by going from 1600mhz to 2133, I gained another ~5 GFlops.