I just purchased a new Radeon with 128mb.....but my computer is a COMPAQ old isn't really a good FLYING computer...so know I need ram what will the RAM do becasue I added the new video card and it didn't help to much becasue it kept stuttering....I know how RAM adds memory and everything though

RAM allows the computer working space in which it can carry out it's processes.

RAM is not a miracle cure, but only a part of what makes a system work.

A computer capable of running a complex flight sim for instance, needs to be a balanced powerhouse of computing strength, with a fast CPU, Plenty of RAM and a good video display system, running on a decent mainboard which supports advanced features.

If you post your complete and detailed system specification, maybe someone here can suggest what will help your particular configuration. Don't spare the details.