[quote='Tsunami',index.php?page=Thread&postID=15860 5#post158605]For Hyperthreading to work properly the program needs to be written to take advantage of hypertreading. [/quote]
Microsoft says, "In general, multithreaded Windows applications perform better when running [b][i]unmodified [/i][/b]on an HT processor than they do on a similarly equipped single-threaded processor." (My emphasis.)

They go on to suggest a way that applications can take special advantage of hyperthreading -- by setting thread affinities in a certain way -- but this is icing on the cake.

This is from section "6.2 Improving Application Performance on Hyper-Threading-Enabled Systems" in

[url='http://download.microsoft.com/download/5/7/7/577a5684-8a83-43ae-9272-ff260a9c20e2/Hyper-thread_Windows.doc']Microsoft White Paper on Hyperthreading[/url]