i7 920 2.67ghz OR Dual Xeon E5472 3Ghz?

I currently use an Intel i7 920 running at 2.67ghz, with 16Gb Ram. I have the option of buying a 2nd hand Mac Pro 2008, here is the spec…

Mac Pro “Eight Core” 3.0 (Early 2008) is powered by two 3.0 GHz Quad Core 45-nm Intel Xeon E5472 (Harpertown/Penryn) processors with 12 MB of level 2 cache per processor (each pair of cores shares 6 MB), a 128-bit SSE4 SIMD vector engine, and 1.6 GHz “64-bit dual independent frontside buses., includes 16Gb DDR2 Ram”

Now my question is which system do you think will be much faster for using with Cubase 7? And if faster, significantly so? I realise that the mac Pro Xeon chips do not use hyperthreading, although the fact that there are two of these giving 8 pure cores would that be better than my current i7 920 chip which is quad core but does have hyperthreading?

Hope to hear from someone in the know.