i5-750 twice as slow as i7-920 in floating point, at same clock speed?

[VirtualLarry]

http://media.bestofmicro.com/E/M/245470/original/Sandra%20Arithmetic.png

Can someone explain this to me?

from: http://www.tomshardware.com/reviews/amd-phenom-ii-x6-1090t-890fx,2613-6.html

 

[alyarb]

SSE registers are logically duplicated in the i7. that's why hyper threading is great for explicitly SIMD apps.

you're doing a synth bench and your test results are going to be very best-case.

see however that the integer shows the i5 very close to the i7? the bulk of the pipeline is shared.

 

[yh125d]

As he said, double the threads, double the performance


Look at the thuban. 75% of the threads of i7, but 20% clock speed bonus, so it's almost as fast