The single most important factor when over-clocking is temperature. So depending on how high you want to over-clock your system your CPU cooler needs to cope with the extra heat that is produced when you increase voltages to sustain your over clock under load. The Intel stock cooler is serviceable but that is about the nicest thing I can say about it. One other thing you need to think about is what work your computer will be doing. There is a huge difference between idle temperatures and when the CPU is under load. I am not a big fan of these artificial CPU stress programs at all, I would much rather play a really taxing game that will kill a fragile over-clock rather than run 24 hours of prime. I have had machines that can run prime day in and day out but failed when I played Crysis within the first 30 minutes. But that is a personal choice and up to you. The point is it is not just getting to the desired over-clock it is being able to stay there when your machine is being pushed hard. Why am I harping on heat management? Simply because most of the time we do need to up the voltage a bit to have substantial over-clock. As you said you had hit 3.6 GHz with no voltage increase. However does that mean you left all settings to auto? Because if you did then your voltage has been increased automatically. Or does it mean you have manually set each voltage setting?
But to answer your original question. There are similarities to over-clocking a P55 chip-set motherboard and the X58 chip-set boards. But it is not exactly the same. Close enough for your needs for it not to be a worry at this stage. The memory controllers are different for one.
What is your desired outcome with your CPU, over-clock wise? For most folks it seems to be the 4Ghz is the desired outcome.
