The Hardwareguide (part 3 of 11)

The GPU (graphics processing unit)

Brands: Asus, EVGA, Gigabyte and MSI are very good. Sapphire, XFX and Zotac are good. HIS is ok. Look for the better heatsink/fan and warranty.

Tiers: A general guide: Sub $100 is low tier, $100-$200 is mid tier, $200-$300 is high tiee, and above $300 is very-high/flagship tier.
Low tier: Play old (pre 2006) games easily, and modern games on low or not at all. Mid tier: Play Modern games, at medium settings. High tier: Play modern games on medium or high.

EVGA GeForce GTX 580

Resolution: Your res has the biggest effect on your GPU's performance. 1920x1080 is very popular at the moment, but a mid-tier/low-tier GPU can still play modern games on reduced res.

Warning: Recommendations are valid at the shown prices. If a recommendation is only available at a higher price, or an alternative is cheaper than usual, then these recommendations is no loner apply.

Alternatives: Consider switching to these "great, but" cards if you can find them with good discounts/combos: 240, 250, 4850, 4870, 5850, 470

HSF: Most graphic cards with the reference designs have similar or identical performance/noise/temps, since the internals and HSF are similar, Only the sticker outside is different.
Cards with custom HSFs may be slightly more expensive, but may have superior cooling, better OC-ability and lower noise. Examples: MSI's Twin Frozr II design, Gigabyte's Windforce design.

ASUS HD 5970

Tips: When comparing GPU benchmark, pay more attention to game performance at your preferred resolutions. Place less emphasis on GPU performance in synthetic benchmarks.
SLI/CF setups may trump single cards in performance, but may have microstutter/temp/noise/power draw/future upgrade issues. A 580 is a great card but its price is ridiculously high.

The best performance for your $$$ is usually in the mid-tier cards. The higher the card, the larger the price increment goes. The priciest cards usually have terrible performance/price.
A general rule: Mid-tier cards scale better than high-tier. nVidia also has (generally) better driver support under Linux.

Remember to make sure your PSU can power your cards (and has enough cables if SLI/Crossfire), and that your case can fit them and provide adequate cooling.