Low power hypervisor pc

[yankees9920]

I am looking to build a low power/low budget hypervisor machine to run WHS and muck around with some virtual machines.

WHS will be kept running and other VMs will be used occasionally (I don't envision over 3 running at once).

I am looking for feedback about which cpu is better. The Athlon x2 250 or the Phenom x2 550. I am leaning towards the 250 since its lower wattage (65w vs 80w) and its cheaper.

I am 99% positive I will use Hyper-V because of the raw disk access (good for WHS) so I am not really worried about Vmware HCL. The rest of my build is planned as:

one of those processors
MSI 760GM-E51 AM3 AMD 760G HDMI Micro ATX AMD Motherboard
4gb ram
1x 5400rpm laptop drive for OS partition & ISO storage
2x 7200 rpm 1TB drives for WHS
1x 7200 320gb for other OS VHDs

Also I am looking to know what I can do to help save on power consumption. Am I able to set the disks to spin down when not being used by the VMs? Can I set the host to go to sleep/wake during certain hours or wake on lan? Open to other power saving suggestions too.

I really want a power efficient WHS, but since I am making a new machine I also want to be able to experiment which is why I plan on using a vm hypervisor.

 

[tormentum]

On the hard disk front, have you already purchased these? If not, i'd recommend the WD Caviar Green's. They have great power consumption ratings. I have 8 of them running in my home SAN. They are a little slower, but if it's for home or if you're RAID-5'ing them, not an issue; they're still plenty fast!
http://www.wdc.com/en/products/products.asp?driveid=559

No, you won't be able to spin down the disks on a Hyper-V box. Hyper-V actually disables most of the power saving features by default, in favor of performance.

 

[yankees9920]

Yeah, I already have all of these disks except for the laptop drive I want to buy for obvious power saving reasons. Are there any ways to improve efficiency aside from the hardware decision?