By Ken Bravio
Most off the shelf computers from stores such as Best Buy or Target have integrated graphics, meaning a base line non-dedicated video processing "card" - in other words, you won't be doing much gaming with a stock integrated graphics chip.
Upgrading to a dedicated graphics card is one of the best upgrades you can do for your desktop - whether you don't have one, or just are looking to upgrade your slow machine.
Keep in mind - if you are upgrading to check and see how big of a power supply is required to power the card. All cards should list this information, and if not a little digging around on the internet should provide that information. You may need to upgrade your Power Supply (PSU) in order to power a new graphics card. So be sure to double check this before spending your money on a card.
EVGA GTX670
This is an NVIDIA graphics card, one of the top 2 players in the GPU game. This is a 2GB card, which a few months ago was considered the top of the line, but in 2013 we will see a lot more 3GB or even 4GB cards. That does not mean this card is not a beast - because it is a beast. Direct X11 capable, PCI-E 3.0 16x and more - you will be gaming at HD resolutions and beyond, with the best graphics settings possible.
AMD Radeon HD7970
Radeon is the competitor to NVIDIA, usually offering a cheaper alternative to it's NVIDIA sister cards. But this doesn't mean they are weaker. The HD7970 is a very powerful card at a great price - probably one of the best "budget" cards you could get for price/performance. With 2GB RAM, a 925MHz clock speed, PCI Express 3.0, this is a BEAST card. It's size shows it too - make sure your case can fit it. It also requires at least a 500w PSU.
MSI GTX 660 Ti
MSI manufactures a lot of cards and this specific one runs on NVIDIA drivers. It has a 915 MHz clock speed, 2GB ram, PCI Express 3.0, and a few other bells. MSI makes great cards with great cooling ability. This one features MSI's Twin Frozr IV feature which keeps the card 14 degrees Celsius cooler then normal. Say goodbye to dust buildup on your card and increase the life of your GPU.
Sapphire Radeon HD 6950
This is a fantastic budget card with AMD drivers - the 6950 is older, but still a beast. A 800Mhz clock speed (that overclocks very well), PCi Express 2.0, direct x11 support, and 2GB video ram is featured on this card. It's truly a power house card for the price (under $200) and is easily overclockable and can reach speeds on par with more expensive cards such as the 7950.