Benchmark Results: 3DMark And PCMark Vantage
The CPU score reveals that there are significant differences in synthetic processing power. The quad-core with Hyper-Threading and eight logical threads is almost able to match the performance of Intel's Gulftown design without Hyper-Threading enabled. Of course, this is a synthetic metric, and we all know that means results can't necessarily be mirrored in real-life benchmarks.
3DMark shows some benefit from having Hyper-Threading enabled. The improvement roughly equates to two or three speed bins (a speed bin being a 133 MHz jump).