I have a WHS running on a 330 Atom. The D510 is a little faster. The biggest problem is expansion. My system is a nettop, and has only 2 SATA ports with the only other expansion other than USB being a mini PCI-E slot. Using more than two drives (highly recommended), results in some of them being USB. If your network isn't Gigabit, then you will likely not run into major issues, but I wouldn't hang more than one or two drives off USB if it can be avoided. As far as processing power, the Atom is slow to open the console, but very few tasks on WHS are CPU intensive. The one thing is that you will not save much power, if any, over the i3 2100. The Desktop ATOM has no speedstep or power saving abilities. The i3 probably runs at lower power when idle than the ATOM, and your WHS will be idle 95% of the time unless you desire to do any transcoding. If you do, you will definitely want an i3 or better. All Sandy Bridge processors have impressively low idle power consumption.