Hello duanebong,
Our experience indicates up to 25% greater throughput using HT. Of course, this was measured on the i7, which has the largest caches in Intel's i3/i5/i7 lineup. Performance is best using a variety of projects, which reduces contention for the same resources. Clean Energy Phase 2 has some potential I/O problems which could slow things down dramatically. Either avoid it or carefully limit it. If your memory or cache is limited, look over Sekerob's estimates of memory used per project and choose projects with a small footprint if you want maximum throughput.

Lawrence

Thanks very much for the quick responses. A 25% improvement for WGC sounds great, and the badge hunting is a bonus.

From some benchmarks floating on the web of other applications (nobody seems to publish WCG benchmarks, though occassionally I can find some for folding@home), I was fearing it would just generate more heat with zero or even negative performance gains. I suppose it's very application dependant.

Does memory speed become a bottleneck when running 8 threads? On my Q6600 quad, scaling was poor when running the 3rd and 4th work units. Does it help to get DDR2000 or faster memory?