The 965 has a +1 cpu multiplier and is also batched higher (probably batched higher) I would go for the 955 get a decent cooler for 20-30 and overclock it abit. It will run cooler making life last longer. And it would get a higher clockrate.
The 955 and 965 are the same chip and OC to pretty much the same level. Since both have unlocked multipliers you can get a 955 and just bump the multiplier up one to get yourself a 965 and save $20, if you want to OC get the 955 and drop that $20 plus a bit more into a nice cooler like the Hyper 212+(get it from amazon not newegg)
With AMD CPUs its super easy. All AMD systems use a 200MHz base clock, the CPU speed is the base clock times the multiplier, so a 3.2GHz AMD CPU has a 16x multiplier and a 3.4GHz CPU has a 17x multiplier.
Intel core 2 systems are a bit more complex because there were different bus speeds, but AMD kept it nice and simple.
So what exactly does the multiplier do? What does having an unlocked multiplier mean?
If u don't know anything abt overclocking, then leave it and get ur self a 965 BE.... it's better to give 20$ rather than getting headache of overclocking.... plus overclocking will void ur warranty too....and 965 has a reduced TDP than 955.....
On normal processors you cant change the multiplier you can only change the base clock, but since there are other systems that base their speed of the base clock it can be a little trickier to work with. Having an unlocked multiplier makes overclocking significantly easier, if you get a good cooler to go with it you just bump the multiplier up by one, check and see if its still stable, bump it up another one, check for stability, until you hit they point where its not stable any more, you can either increase the voltage a bit or drop the multiplier down one to where it was last stable.
rohn_avni, the 955 and the 965 have the same TDP rating and if both are the C3 stepping the 955 will use less power.
edit: you dont mess with voltage normally until you hit a speed that its not stable at its stock voltage, then you bump it up a bit to where it is.
You start with adjusting the multiplier and get as close as you can with that, you can then adjust the base clock to get the max OC out of your system but you can get to within 100MHz of your max OC without touching the base clock speed.