Well i've devoted a core to my two 3850s now and the results are pretty impressive
on the three remaining cores [at 3.1ghz] you get about a WU every 20 hours. Not too shabby, there's better performance out of C2Qs but what makes up for it is the crossfire'd videocards pulling their weight
GPU work Units go fast.
I get a percent every 2 minutes.
In an two hour work unit worth between 100 and 200 points [well 98 and 196] that adds between 1200 and 2452 ppd to my total
that on top of the roughly 1900 ppd i get out of the quad already, you can build a nice machine with a radeon or two.
FX-6100 @ 4226 mhz, Cooler Master Hyper 212 Plus cooler with too much MX2 on the bottom, 8 GB of Slow DDR3, Packing a Velociraptor, Radeon 6950 which is big and black, Corsair 600T Special "Imperial Stormtrooper Wannabe" Edition.