c2d e7200 speed and e5200 question

One is 45nm and the other is 65 nm. The 45nm will allow higher overclocking and will be cooler.

Both are 45nm. Cache is a big factor for core micro architecture so yes, the E5200 needs to OC a bit to make up the difference in general.

yeah i just googled it both are 45 nm

so basically there's no difference at all??!?!? except the extra mb cache?

The extra L2 cache (while small) helps in games but if the price difference is a concern then just go for the E5200 and OC it.
In other words a slightly greater clock speed can compensate for the lesser L2 cache.

There is another difference. The E7200 runs on a higher FSB (1066). This should allow for better performance too.

I have my E7200 overclocked to 3.25GHz very comfortable and to 3.5GHz within safe voltage limits. I really doubt the E5600 can beat the performance on this E7200.

It really depends on which programs you're running, how CPU and cache dependent the programs are. For both chips, the effect of cache also diminishes slightly the higher they are clocked.

The E5X00 and E7X00 are the same core, but the E5X00 runs at a slower FSB speed and has 1Mb less L2 cache which is disabled on the core. Basically it all comes down to Intel's binning.

The difference from 4Mb to 2Mb L2 cache at identical speeds with the first gen Core 2 Duo (E6600 vs E6400) was about a 3-4% performance increase in games. Clock for Clock, they are somewhat close, but the real benefit is the OC ability the E7X00 series has. The E5X00 are known to be FSB wall limited.