Upgraded to a Downgrade! WTF! Please Help!

Hello, I'm here because i've crossed the line between calm and controlled to insane. The story so far....

I recently upgraded my CPU from a AMD athlon 4000+ 2.4GHz (Single Core) with 2GB budget DDR ram and a **** motherboard to:

Intel Q6700 (4 x 2.6GHz)
ASUS P5KC AiLifestyle Series iP35 motherboard
Kingston 2GB (2x1GB) DDR2 1066MHz/PC2-8500 Hyperx Memory
Arctic Cooling AC-FRZ-7P Freezer 7 Pro CPU Cooler
550W PSW

The problem is having upgraded i've noticed that games such as Crysis Warhead are running slower or at the same speed! When I had the amd 4000+ system i could have everything on Mainstream setting and it would run without lag, now it lags at those settings! WTF!

What happens exactly is that it will run smoothly and then freeze for a couple of seconds and then run smoothly again and then freeze again and so on. This happens with every game i play including mass effect, world in conflict & GRID. I had no lag when playing these games on the AMD 4000 on the same settings. I did the installation myself so i'm thinking i messed up somewhere, but I don't know where it could be.

When i check the PC via the bios or windows it tells me everything is installed fine and running at the speed it should. My computer usage is also idle at around 1 - 3 % usually. Shouldn't things be running better? I even overclocked my Q6700 to 2.8Ghz and its still the same. Somethings wrong.

Any help would be great. P.S I have a 7800GTX graphics card (cant afford to upgrade yet) which was used on both systems

Windows was not reinstalled, would this help in anyway? All the drivers have been updated to the appropriate and latest ones available including the bios. Cheers.

I was always told you HAD to re-install windows after you install a new MOBO!
Also i never got windows to boot with a new MOBO. So yeah i think you need to.

If you upgraded a single core CPU to a multi core CPU, windows needs to use a different "hal". This can be done by either updating the windows CPU driver, or simply doing a restore install of the OS. This will allow it to use more then one core of your new CPU.

If your new CPU hits 80c, it might be thermally throttling itself. The idle looks good, but your under load temp is to high. You have probably upped your voltages to high. I would back them down a bit, or even remove the overclock until your system is stable again.

Without knowing anything about your PSU, its impossible for me to say. 550W might be a lot, but you have no idea how clean that power is, or how many amps are available for your GPU and new multi core CPU. Both the CPU and GPU draw power from the 12V line, so if it can't supply enough power, one or both will suffer. In addition, if the power on that rail is "dirty", you might have issues. I don't think this is the problem, but you should keep an eye on it.

O and the cpu voltage is on 1.3250 in the bios? cool?

If you are not OCing, the Voltage can likely be reduced quite a bit.

I have a Q6600 that is running at stock speeds, but I've drop the voltage to 1.15 or even lower. ( I need more cores than I really need speed for its particular function, so that is the reason for the odd setup on that particular machine.)

While it could be lower, 1.3 is fine. You should double check your heatsink, push pins are a b!tch.

If your using the wrong CPU driver, none of this might matter however once your reinstall is done.