XEON familiy 5000, 5100 or 5300?

Hi,

I'm about to buy a few new servers, and I'm trying to determine if I
should buy XEON family 5000, 5100 or 5300 processors.

For about the same price, I can have:

2 Dual-Core Intel Xeon 5060, 3.2 GHz, 4MB
2 Dual-Core Intel Xeon 5130, 2.0 GHz, 4MB
2 Quad-Core Intel Xeon 5310, 1.6 GHz, 4MB

I have a few queries that take about 4 minutes each to complete on a
single Pentium 4, and all of them are CPU-bound, with the whole database
in RAM. With the new system, I expect a performance boost, of course!

If I'm not wrong, a single postgresql sql query cannot be spread over
two processors, but can it be spread over multiple cores? If that's
true, does that mean the best CPU would be the last one, although the
clock is lower that the one of the other processors?

Thanks for the infos,

Cheers,

---------------
Philippe Lang
Attik System