Most inexpensive computers come with an integrated video processor on the motherboard rather than a dedicated video card with its own video processor and video memory. This is why you can buy a fast, modern PC with lots of memory and it still won't run your flight simulator worth a poop.

The measure of a video card's power is based more on the GPU (graphics processing unit) rather than the amount of video memory on the card. The following chart will provide you with a good idea of the relative strength of a video card:

http://www23.tomshardware.com/graphics_2007.html

Real Flight G3.5 and G4 can be fairly demanding, but you don't necessarily need to spend $280 for an Nvidia G8800GT card to run it. The Radeon 2600 Pro, GeForce 8600 GT, and Radeon 2600 XT are all readily available in the $80 to $100 price range and any of the three should run Real Flight like lightning.

Video cards are usually available for far less at online resellers like www.newegg.com or www.mwave.com than the prices they sell for at your local Best Buy or Office Depot.

Good luck and good shopping!