Hyperthreading incompatibilities

[ChipDeath]

I know software exists which is incompatible with hyperthreading, but I was wondering if anyone has a link to some info about exactly why. I.E. what is it that's different about a 'normal' SMP setup and a 'virtual SMP' HT setup, that screws up certain applications? (or would they all still suffer on a classic SMP rig anyway)

Anyone know a good site for this sort of information? Just because I'm curious about it, no other reason.

I was reminded of this earlier because we just installed interbase 6 on a P4C 2.6 HP system, and it suffered certain problems until (after a quick web search) we turned off HT.

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[sonoran]

Not sure what makes some software behave badly. I think slvr_phoenix had some ideas on that one.

BTW, I found this in the Interbase "What's New in 7.1" list:

<font color=blue>Hyper-threading support allows those with Intel® Pentium® 4 and Intel® Xeon® processors to take advantage of the "virtual processors"</font color=blue>

 

[Guest]

I'm not positive there are any applications that are specifically incompatible with HT; but I do know quite a few drivers used to be incompatible with SMP, so it wouldnt surprise me those drivers are also incompatible with HT. I think I heard this about (old) ATI drivers, but don't quote me on that.

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