Video Card Upgrade Confusion?

[.:PTB73:.]

Hello All,

I'm getting ready to upgrade my system (for gaming, BF3, DIABLO III, Crysis 2 & Metal of Honor Warfighter etc) & have a few questions about some of the video cards I'm looking at.

I've been looking at new graphics cards & I'm a "little" confused. lol

Why is it that some of the 500 series are more money than some of the 600 series cards.. & why are some of the 400 series more than the 500 series?

I thought the higher number, 660 GTX would be better than a 580 GTX no.. what makes the 580 GTX better than a 660 GTX?

I've looked at the specs on the cards & I just don't get it.. BRAIN FART!!

What are the specs to look for?

Core Clock?

Boost Clock?

Cuda Cores?

Effective Memory Clock?

Memory Size?

Memory Interface?

What is the best Geforce card I can get for $250.00 & be able to play the above games on ULTRA @ around 30+ FPS?
Thanks All, Phil B.

Current System Specs:
Case: Cooler Master HAF 922
Motherboard: EVGA 680i SLI A2 122-CK-NF68
CPU: Intel Core 2 Duo E6600 2.40GHz
Graphics Card: EVGA 8800GTS 640MB
Hard Drive: Western Digital VelociRaptor 300GB SATA 6 Gb/s 32MB Cache16MB Cache
RAM: OCZ 2x512 & 2x1GB Gold GX XTC PC2-6400.
Power Supply: CORSAIR TX650W

 

[Knufire]

The first number in the model name is the series number. 5xx, 6xx, are all a "family" of cards.

The second number dictates which "member" of the family that card is. Lower is lower end, higher is higher end.

Usually, when a new family/generation of cards come out, the performance of the new generation card is equal to the member above it of the previous generation. For example, a GTX580 (5xx generation card, x80 which indicates most powerful single-gpu card) is about equal to a GTX670 (6xx generation card, x70 which is one step below the top) in performance.

Any reason why you're only looking at NVIDIA? There's the 660Ti at $300 and the 660 at $230. If you consider AMD, there's the 7870 at around $240-250.