AMD Phenom II X4 965 Black Edition 3.4GHz Bottleneck?

Depends on the game. Probably since your at such a low resolution it will be the weak point instead of the GPU but that's not necessarily bad. theres ALWAYS a bottleneck somewhere

would overclocking make any difference at those resolutions?

In short. No.
Your CPU doesn't even bottleneck a HD 7970.

Clocking my 975 from 3.6 to 4GHz does improve frames slightly (+10Fps avg on C3) but it seems that the Cpu pushes harder and card usage drops so its more balanced,
depending on your cooling being up to it I'd say check out the BE Clocking guide over in the overclocking section and clock the puppy up some  
Moto

so not overclocking the CPU wouldn't be an issue running the 7850 at 1600x900 resolution, the games that it will be running are BF3 guild wars 2, crysis 1,2 and 3 Tomb Raider ect mostly modern games what sort of setting would I be looking at?

Take C3 as your guideline here,
run this on your pc, it will probably say your chips weak and gpu is lacking
http://www.yougamers.com/gameometer/10566/
Then clock it to 4GHz and rerun it, it should make a vast difference,
I run C3 on very high (Except shadows, High) and Fxaa, 3.6GHz gets me about 50Fps and 4 gets a solid 60
I'm slightly ahead of you on Gfx though with two 6950 2gb's

Moto

Cheers, what resolution you running at as 1600x900 is tops for my monitor.

7850 at 16x9 will be perfect.

thanks i'm becoming very happy with my low budget choices........ mainly because this place has had a big input in every choice

I'm at 1680x1050 on one monitor so comparable
Moto

So I'll be looking at very high settings and maybe a bit more fps wise if I mildly overclock her

Yup, As I said, knock aa off if you struggle and drop settings you can live without like shadows, but its perfectly playable on lower settings or at slightly lower frames,
Moto

thanks a lot you've been a big help think its a wise choice while i wait for steamroller

No probs man, glad to help
Moto

Managed to get a Sapphire 7870 Ghz edition for £163 had to do it, already bought it, but was it wise lol!!!

It won't be a massive boost in and of itself but crossfiring the two...
 
Moto

2 7870?

Aah, sorry, I thought you already had the 7850 mentioned in the original post, and thought of crossfiring it with the 7870 you've just bought, obviously I misunderstood and thought you had bought that as a second card, when actually you only have that one card
Moto

Ah ok no I bought all the bits today was going for the 7850 1gig but price went up so saw the 7870 for £15 more and went for that

Big mess up the company supplying the CPU and GPU have shafted me and I waiting for refund

had to go with
XFX Core Edition Radeon HD 7870 2048MB GDDR5 PCI-Express Graphics Card + 2 FREE GAMES! £166
FX-4300 3.80GHz £90

will the FX-4300 3.80GHz be as good as the X4 in gaming?

it will do just as well, they are of the same class of gaming cpu

Thank god lol

not really;fx-4300 is 2 cores/2 modules,and much less performance than 965 BE