Which combo: i5-2320 + HD 7850 or i5-3450 + HD 6870?

Which combo should I choose bw:
1. core i5 2320(3 ghz) and Sapphire HD 7850 1gb,or
2.core i5 3450(3.1 ghz) and HIS HD 6870 iceQ X

Prices are the same...it will be used for playing game ssuch as AC 3,Crysis 3 etc

Why not the 3450 and 7850?
Depends where you live but the 1GB 7850 is only slightly more than a 6870 which is an older generation and a bit overpriced nowadays.

Its bcoz 3450 and 7850 combo shoots the price by ~40$,its well beyond my budget
so which one do you recommend??
Also is it compatible with my Intel DH55TC mobo?

Your mobo is socket LGA1156, whereas the processors you've chosen use the newer generation 1155 socket. So if you wanted to upgrade the CPU you'd also have to get a new mobo. It's only 1 pin difference but unfortunately an i5 2xxx or 3xxx won't fit in your current mobo.

It would be useful if you listed your complete PC spec, your max budget and where you're buying from, it might be that you don't need a CPU upgrade anyway.

$40 extra is well beyond your budget? Well, okay..

My complete PC spec-
Cpu-core i3-530
ram-4gb 1333 mhz
Gpu-gt 240 1 gb
Hdd-500 gb seagate
mobo-intel dh55tc
monitor-samsung 22" lcd
psu-corsair 450 W


I guess thats it...
I live in India,so its hard to convert INR to $ as it hardly matches due to high import taxes...
I will also upgarde my RAM to 8 gb!

Keep your existing mobo/CPU and get the 7850. That GT 240 is weak and you should see a big improvement with a GPU upgrade.

The i3 530 is a couple of generations old but it has 2 cores and 4 threads and is just about ok for gaming. Getting a new i5+mobo will cost quite a lot and you won't see much of an improvement.

Thanks,but recently I have seen my pc slowing down quite a lot,which may be due to the cpu
And I hope to use the i5+mobo for the next 2 years,which will not be possible in case of my current cpu,which will eventually need upgrading
so I am hoping to be future proof with i5+mobo

CPU's don't degrade in performance over time, try defragging your hard drive and scan for viruses, those are much more likely reasons for your slowdown.

Ok,thanks....
but before defragmenting I analyzed my hard disk..it showed that my C disk is only 1 % fragmented whereas the other 3 disks are 0% fragmented

Clean your temp files and registry using Ccleaner.

Ok,will try!