What's the Difference between AGP and PCI-E

Hi All. Was wondering if the upper-techies could give me some insight. I know quite a bit about comptuers, except for this.. graphics card ports.

You have AGP and PCI-e...

You can get the same modern hi-performance cards on both card slots but whats the main difference? What if i have a a decent PC but all it has is AGP and I but a Radeon HD 4870 or however high they are for AGP and use it. Will it be any different from PCI-e?

Thanks.

PS: I don't plan on buying anything, I'm just looking for information on what the differences would be with identical cards but with different ports.

AGP - 8x
PCI-E - 16x (more bandwidth)

PCI-E > AGP

AGP is the older generation even though it is less bandwith its still fine but most newer mainboards would not support AGP.
the fastest video cards are PCI-Express and are more accepted and easier to obtain.
also with the Radeon HD 4870 if you processor is too slow it will effect you overall performance. and check the prices as AGP cards are usually more expensive then the PCI cards.

Also the slot is totally different shape -
make sure of what slots you have available
anything new will have pci-e , make sure its pci-e2.0 or better if you are upgrading your mobo

agp is found as far back as pentium 2 PCs and is almost phased out
ATI is about the only ones making current gen AGP cards. Nvidias AGP units are old GPUs (Direct x 9).

-talk to me in guild chat if u see me on I have both AGP and PCI-e cards running in various PCs

Also note that there is also a PCI port.

PCI < AGP < PCI-e

A good AGP card (like 512MB with direct x 10) will run GW beautifully, but PCI-e is faster.

PCI-e will have more options and tend to be cheaper since high quality AGP cards are getting hard to find. Although all cards are dropping in price right now so it's a good time to buy.

Don't forget to check the power supply requirements on the card you buy.

the amount of vRAM on a graphic card hardly denotes how well it will perform. you have to look at the type of vRAM, its speed, and its memory interface. that's even before getting into how good the GPU is. just gotta throw it out there.

Thanks guys, I knew PCI-e was better, just didn't know how far behind the same cards would be running on an AGP bus... A while ago I was lookin to upgrade my old PC with a Radeon X1000 Series (this was quite a few years ago) but I figured the CPU was much too slow and there was a mobo memory limitation for the ram (lame ass). I have a fast comp to play GW, CoD4/5 on so I'm not gonna be buying anything anyway for a while.

Anyways thanks.