What makes one graphics card better than another?

What matters to most is the FPS it makes.

Others care about:
length of card
heat it makes
how much noise it makes
reputation of the company they buy it from.

Start here to see where they all fall in terms of performance, then google prices for each card that you see in the same category, because the prices are changing daily.
http://www.tomshardware.com/reviews/gaming-graphics-car...

How many cudas or shaders or coochiemamas it has doesn't really tell you as much as the actual tests and recorded benchmarks.

Which is faster, a 4 cylinder Lotus, or an 8 cylinder Crown Victoria? See?

Do not compare GPUs by specs, say a GTX 590 which has about 600Mhz, compare it to a 6570 which has 650Mhz Core clock. You definitely can't say that 6570 is faster. Tom's hardware has a nice hierarchy of graphic cards if you don't want to go around and search for a benchmark for each individual card:

http://www.tomshardware.com/reviews/gaming-graphics-car...

As you can see GTX 580 is 2 tiers higher, which means it is faster than 560 Ti.

What makes the 580 faster than the 560ti is a larger memory pipeline, 256bit vs 384 bit. The number crunching is done by the cuda cores. More cores, equals more number crunching, faster graphics processing. You might be able to get a few more FPS by playing with clock speeds, but most of the time it's not necessary.

some factors when deciding on which gfx card is better for gaming:
gaming performance in different games and at different resolutions, settings etc.
gfx card architecture, gpu fabrication process,
performance per dollar, power effeciency, gpu cooler performance,
total price, warranty
for example, between gtx 560ti and gtx 580,
http://www.techpowerup.com/reviews/MSI/GTX_560_Twin_Fro...
gtx 560ti has better perf/$$ which makes it a better card than gtx 580 imo.
if you want raw performance, the gtx 580 woul be better (actually, a radeo 7850/gtx 680 might be even better). but if you have a limited budget for gfx card and do not require that much performance, the 560ti would seem better.

I seem to be the only one to ever say this but I think it's important as well as true. ATI/AMD drivers are buggy. I've had several over the years and the difference compared to Nvidia is immediately noticeable to me. Others will tell you that Nvidia has driver issues too and that's true. However they fix theirs. AMD/ATI bugs are often so random and intermittent that they cannot be reproduced and therefore cannot be fixed. Also, all the hype about a few extra FPS is just a pissing contest. It's a game of diminishing returns. Those extra FPS are the most expensive you'll NEVER see. They don't add a thing to the enjoyment of playing a game. If you're into bragging rights then I hope you can afford it. Otherwise put your money into a solid performing rig and splurge on something meaningful.

In this case, simply put...

More CUDA cores (512 vs 384). More cores to process information.

Larger Memory Interface (384-bit vs 256-bit). Wider bus to transfer that information faster.

This is what makes the GTX 580 perform better than the GTX 560Ti.

@ ram1009. Easily turned into a flame war but i totally agree with you.

Actually tell you what. The only reason i tried Amd was because i seen an hp laptop (while ago) with an ati 4650 play original aliens vs predator game perfectly where as the drivers provided with my older pc's 7800gtx played poorly, and i tried many driver versions. Ati just seemed to win my heart at that moment.

Not until i experienced problems with Rage on my main rig (to this day) did i compare to my 2nd with a 580gtx and seeing things have turned around quite a bit and for some time now ive noticed by what others have genuinely said.

Nvidia's software developers are a bit further ahead than amd/ati i think.

Best answer selected by AntaresX.