ASUS P5K64 WS - where 4 x 16 = 20

[HEXUS]

ASUS offers no fewer than 12 motherboards based around Intel's P35 chipset. We've already reviewed two, the P5K Deluxe and P5K3 Deluxe, and now we're checking out the P5K64 WS workstation board. This has four PEG slots but not enough lanes for four graphics cards to all run at full width.

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[BUFF]

nitpicking I know but
"Processor support All Intel LGA775 CPUs except Celeron Ds"
I think that you'll find that 533fsb CPUs like the D805, 519, 506 & 505J aren't.

Other than that the usual thoughtful Hexus review.