5GHz is overcloker extreme, if you are not an expert and just trial and error should not brothers. better just play it safe it would be better for example 4GHz course it was a good one. 5GHz only benchmark for the race, and not for daily use. only suggest
Easy 5 ghz oc would be on the sandybridge, unless you can afford a really good heat sink (Like the coolermaster v8 - i think thats the name), but I would still doubt you can hit 5 ghz stable.