I've read that 71C rumor a lot of times in various threads but so far I've found nothing 'official' from Intel about the 71C.If 71C is the limit

Apparently Intel are very cagey, and won't even reveal throttling temp.

When I talked to an engineer at Intel, I asked him for information on what temperatures the Core i7 CPUs will throttle at, and what temperatures are considered normal. I was surprised to hear him say that he didn’t know the answer. He said he’d find out. A few days later, I got a call back, and I was even more surprised. He says that information is a trade secret, and Intel is not making it public. What?!?

http://www.pugetsystems.com/blog/2009/02/26/intel-core-i7-temperatures/And didn't Phil Taylor say that tests with HT revealed thread collisions and stutters, so FSX was not coded for HT? Forgive me if I remember wrong.Regarding temps... most try to stay below 80 core temp. I think that's sound advice.

I have always had hyperthread running on my I7-975 CPU. I tried this setting, and got stutters in animation advancement. Removed it, and went back to smooth advance. My hyperthreading has always been good for me. What I did notice though was twice as fast initial texture loading after FSX startup. That was right out there....

Thanks for the feedback. Looks like my testing for this tweak was less than adequate for all flight environments. I have 'advanced animation' enabled as well but didn't notice any problems, though I rarely fly into the large airports nor do I have car traffic enabled, for with the terrain/weather settings I like to use those two things kick my system in the teeth regardless of any AffinityMask setting. As usual for FSX tweaks, it's always YMMV.When running FSX without any AffinityMask setting when HT is enabled, all its execution threads only run on the phyical cores (logical cores 0, 2, 3, 6). My guess is that when any AM setting is specified when HT is enabled, there are some FSX threads (fibers?) which run on logical cores that are not specified in the AM and this might cause the incurable HT thread collision problem (I was hoping I found a cure for that, drats!). I'll do some more testing...