Here are my results from my 920 with HT and Turbo disabled (I have screen shots if needed).

XP32 920@2660

All 4 cores
CPU time used: kernel 0.41 seconds, user 416.31 seconds, total 416.72 seconds.
Elapsed time 105.67 seconds, CPU vs elapsed time ratio 3.94.
Render averaged 2480.73 PPS (629.07 PPS CPU time) over 262144 pixels

Single core
CPU time used: kernel 0.13 seconds, user 409.80 seconds, total 409.92 seconds.
Elapsed time 530.30 seconds.
Render averaged 494.33 PPS (639.50 PPS CPU time) over 262144 pixels