That's the reason I asked about the motherboard in the system which is reporting such good performance.
That said, I would have thought that if one X5500/5520 chipset motherboard has latency issues, then others will have too, but maybe not.
Anyhow, the spec for our rig has evolved, the system has been ordered and is currently being built - luckily I only needed one extra mortgage on my house to pay for it!
Spec is Supermicro X8DT3, 2xIntel Xeon W5580 (3.2GHz), 24GB Ram in 4GB modules (this way the memory bus can still run at 1333MHz because there's only 1 DIMM in each channel - this mobo has 12 memory slots), Vista 64bit Ultimate, mixture of 1TB SAS and SATA drives, 512MB 9500GT Graphics etc.
It should be as fast as current components allow. I'll post as soon as I have some results. If it doesn't work I'm in deep trouble!!
Jules
http://www.trailermen.com