Video Cards on E521?

The 8600 GT PCI-Express slot card will work just fine, it will not need a power supply upgrade either.  Or go one step up the performance ladder and get the better 8600 GTS card and this to will work with your stock power supply.

Difference with the two cards is that the GTS version you will have to hook up the extra molex power cable to the back of the card and these cards normally come with a molex Y power cable but you will soon learn you probabley cannot use it because your system may not have enough 4 pin power connectors available, so there is a solutions below.....

Your system may not have come with enough 4 pin power input connectors from the power supply to connect to the required molex Y power cable that is necessary to power the video card.

Below link takes you to a site that sells a Molex power cable that will work for your system. Its a 6 pin to 4 pin connectore that eleminates the need for two 4 pin connections, only need one. The 6 pin end goes into the video card, and the other end ( 4 pin side ) goes into a free available 4 pin power input that comes from the power supply.

http://www.newegg.com/Product/Product.aspx?Item=N82E16812201004

Or…..

A SATA to 4 pin adaptor to convert those unused SATA connectors on your PSU to the 4-pin Molex connector instead.

http://www.performance-pcs.com/catalog/index.php?main_page=product_info&products_id=20580

Newegg has them as well for the SATA converters

http://www.newegg.com/Product/Product.aspx?Item=N82E16812263002