That would be no, my 7800GTX 256 SLI rig as well as the 7800GT setup can't even run BF2 smooth with a 1Gb ram. So youre gonna need a 2Gb of ram regardless if you the 128 or 256 graphics card or the 7800GT.
I have used value card before and they performed well, but it's always better to match all your ram.
I have mixed both high performance and value rams with different capacity and speeds before running BF2 and they performed with no problem, but not all rams are compatible.Also mixing ram with different speeds will cost you for the motherboard's bios would set the speed of that of the slower ram.
So it's best to match the rams manufacturer, model, speed and capacity for compatibility and performance.
Does that answer you question? 😀