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Old 2004-01-30, 19:59   #6
TauCeti's Avatar
Mar 2003
Braunschweig, Germany

E216 Posts

Originally Posted by nomadicus
If you have Windows XP, you can leave HT on but for each % on the second virtual processor means that prime95 runs that much slower (the reported 20-30% boost with hyper threading enabled does not apply to prime95 due to its optimized assembly code).
That is true if you exclusively use the system with prime95. If you also use the system for 'normal' work or simultanously participate in other DC-projects with that box, using HT gains up to 60% 'free' performance (for both projects combined) with Win XP.

How much performance you gain depends on the kind of workload the programms have. One more extreme example (close to that 60% gain) is mixing the not-bandwidth-limited prime95 TF workload above 2^64 (Integer SSE2) with the memory-bandwidth-limited NFSNET client (no SSE2).

It is also interesting that the power consumption of the CPU in the aforementioned setup does not increase.

Tau 'HT' Ceti :)

Last fiddled with by TauCeti on 2004-01-30 at 19:59
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