10.... I'd bet something more like 5. And Windows 8 will need a quad core 5GHz processor, and the whole PC will be connected to your home duct work to replace the heat pump.
But the secretary will still have to add a space heater to her cube because it is too cold in the office. While the rest of us die from heat exhaustion.
While at the same time someone posts to slashdot from an 8bit uProc with 32K of ram, on which he just installed linux.