Does a processor upgrade increase framerates?

[Jango]

I am thinking about upgrading my current E6550 Core 2 Duo 2.33Ghz processor to a Q6600/6700 Core 2 Quad 2.4/2.66Ghz processor.

I have recently upgraded my graphics card to a GeForce GTX 260 896Mb, which has increased framerates a lot on Crysis but it is only at 15-20fps on Very High settings.

Would the new processor increase framerates to around 25-30fps, or make much difference at all?

NB: I am not interested in overclocking, as I won't be upgrading the heatsink when I put my new processor in and I don't want it to overheat.

 

[Jango]

But I am worried it will overheat as I will probably be buying the processor chip on its own without a new heatsink. Would my current one be OK for overclocking? Would a freezer 7 pro work with my LGA775 motherboard?

How much do you think it would increase the framerates by (with and without overclocking)?

 

[Jango]

If I do overclock it, then surely it won't be as good as a quad-core, GTA4 and Resident Evil 5 both recommend a quad-core and so will games in the future.

If my overclocked dual-core would be good enough for the future, which good after market stock coolers do you recommend? Would they work with my PSU and LGA775 motherboard?

Here are the details on my PSU sticker:

(H.E.C) HIGH-QUALITY EVOLUTION COMMITMENT

HEC-550TD-PTE
__________________________________________________ _______
AC INPUT:..|...230Vac 50Hz 7A................................................ .|
__________|_______________________________________ _______|
DC OUTPUT:|.+3.3V..|..+5V..|...+12V1..|..+12V2.|..-12V...|..+5Vsb.|
__________|_______|______|________|_______|_______ |_______|
MAX.A:......|..30A....|.38A....|....18A....|..17A. ...|...0.3A..|...2A.....|
__________|_______|______|________|_______|_______ |_______|
....+5V8+3.3V COMBINED 185W...........TOTAL OUTPUT 550W..........|
__________________________________________________ _______|

 

[Jango]

It can handle my GTX 260 896Mb graphics card, and they are huge. I don't really want to buy a new PSU...

You say that around 450-550W would be fine, but it is 550W.

 

[Jango]

So you are certain that it won't work? PS: Thank you for your help so far

 

[Jango]

Would it be able to handle any quad-core processors at all, seeing that it can't handle the heatsink needed to overclock my current one?

 

[Jango]

So, it isn't the heatsink that is the problem, it is the processor?

If not, would I be able to upgrade my processor without upgrading the heatsink?

Although, I could just buy the processor and if it doesn't work i'll sell it on eBay; as that is where I will get it from. But I would still like you to answer my questions ^^.