In terms of synthetics, Zambezi won't give you anything. Real world performance you won't notice that it's not the cream of the crop.

Personally, I'd stay away from it. Matt had it right, 2500k Intel and overclock it to 4.5ghz

Memory timing doesn't matter much because so much latency is introduced with DDR3 that unless you can get a CAS 7 or lower it won't really benefit much unless you run the same benchmark 10 times in a row. At that point, who cares?