central processing unit  

That's tricky and a bit difficult to do. That's high for a computer, but you would have to spend a lot of money and look for a processor that's high. Google the speed and see what you come up with. I don't know without a bit more detail how else to answer you. Though you must want a lightning fast computer.

core 2 duo and the quad core processors with a clock speed more than 2.66 can give a good performance but if u r looking for a 5.00ghz i don't think that is now available also if gets the cost is extreme.so for good performance look those i5&i7 series of Intel those work good

use AMD Phenom X4, assemble your own desktop, it even surpassed the 5.0ghz test. What are you a Hacker?http://www.mylot.com/w/discussions/2231386.aspx

you canget the same performance by using a dual core processor using 2.5
ghz each core hence you get a total of 5ghz processor.

lol no 5 ghz processor is not yet launched I think you need to wait for 2-3 yeats more before Intel can lanch this processor in future

i don't think of that as a 5ghz maybe the said one in here you should use a Dual Core 2.5 because it's double then it will give a 5.0ghz speed.. I'm using a 3.0ghz CORE 2 DUO that will make a 6.0ghz more with a 2CORE and 2Thread with a Cache of 4mb it is so fast in performance that Windows7 is just like an windowsXp running.