GPU Bottleneck questions

[Leetian]

So I had originally planned on buying a z77 extreme 4, i5 3570k, and the GTX EVGA 760 superclock. I currently don't have enough money to afford all three of those items so I was wondering what it would be like if I just bought the 760. I have a PCI 2.0 slot on my motherboard and I've heard that a CPU can bottleneck your gpu. My CPU is the AMD 4300 and my motherboard is the GIGABYTE - GA-72LMT-S2. I've heard several answers on whether or not a PCI 2.0 slot has a noticeable bottleneck for a GPU that prefers a 3.0 slot. I currently have the Radeon 6670 if that is of any use. So for starters, can my computer even run the 760 superclock? My PSU is the corsair 600w. If any more information is required just ask.

 

[ksham]

It can run it, but the CPU is weak so you will notice bottlenecking. That's not to say that it won't work.

 

[leeb2013]

There will be no performance loss using the 760 on a PCIe2.0 x16 slot compared with a PCIe3.0 x16 slot. I tested a GTX680 and there was no difference. Also, most mobo with SLI/crossfire run the two slots at PCIe3.0 x8 which is equivalent to PCIe2.0 x16.

The GTX760 will perform 5-6 times better than your 6670. The FX-4300 will be a small bottle neck in some CPU intensive games, like BF4, but others won't be much of an issue.

 

[Leetian]

How much of a performance loss would I notice with my CPU? I do plan on upgrading in a few weeks once I get more money, but just for the time being.