atlantisshak, you can use a graphics card with ANY graphics ram memory.
A graphics card has it's own Processor, and graphics memory.
Doesn't depend on the system resources, ( Processor and Ram Memory)
GPU = Graphics Processing Unit, the graphics card's processor,http://en.wikipedia.org/wiki/GPU
Doesn't matter if you use a graphics card, that has GDDR3, or GDDR4, or GDDR5, graphics ram memory.
I do however, recommend using a PCI Express graphics card based on the 2.0 technology. (PCI Express 2.0), and NOT the PCI Express 2.1 technology.
Could have problems.
For additional questions please post in a Comment.
Make SURE you,
1) Windows running on the computer, install the graphics card's Installation Disk. (CD disk)
AFTER loading the graphics card's 'Control Panel', and drivers,
DO NOT RESTART.
Close all windows, go back to the desktop screen. Shut the computer down normally.
THEN unplug from power, AND follow Anti-Static Precautions.
Physically install the graphics card. Plug the monitor into the graphics card. Close the computer case.
Plug the computer into power. WAIT 1 minute, turn the computer on.
IF you do not, you stand the chance of driver conflict.
When a device (Such as this graphics card), is installed on a computer, Windows 'break it's neck' to find suitable, matching drivers.
If THE drivers are not there, Windows will match up one of it's
THOUSANDS of generic, one size fits all, drivers.
This = NO.
Could cause a driver conflict.
Windows: " Which drivers do I use? These or THESE?"
[ If you install the graphics card FIRST, THE drivers are NOT there.
Then you go back, and do install the drivers, there may be a driver conflict ]
Small pieces of software that allow the Operating System to communicate with a device.
Some O/S examples are Windows XP, Windows Vista, and Windows 7.
The graphics card is an example of a device.
[ When you put the Installation Disk in the optical drive's tray, and close it, the graphics card's software will come up. Go for the option with the 'Control Panel', AND drivers.
Example; For an ATI Radeon graphics card, the 'Control Panel' is ATI Cataylst Control Center ]