Hi sake_hf,
For any memory OTHER than Rambus (RDRAM), a very good online place to determiine what you need and its price and to buy SDRAM from is at:
http://www.crucial.com/Crucial has the best online configurator that there is and their prices are very competitive if not the best online.
I have Rambus RDRAM in my computer and Crucial doesn't carry this type of memory. But it carries every other type so you should be cool going there.
In any event, at least you'll learn the approximate price of your SDRAM.
512MBs (plus) is the desired amount for CFS3 but 256MBs will definitely show you a great performance boost over 128MBs.
Here are my specs... I'm always upgrading this or that.
Alienware Intel D850GB mobo w/P4_1.3GHz 400MHz FSB CPU upgraded to a P4_2.0(A) with the PowerLeap PL-P4/N adapter and then finally to the P4_2.6GHz. I'm tired of smearing thermal grease!
Sony 21" Multiscan E540/B
WinXP Pro_SP-1
512MBs PC-800 RDRAM
Radeon 9700 Pro w/Catalyst 3.4 Driver Suite
DirectX_9.0
45GB 7200RPM IBM Deskstar
Creative Soundblaster Live! Value (yeah, I know!)
Klipsch ProMedia 4.1 speakers
U.S. Robotics 56K Fax PCI (ain't offered broadband here yet)
HOTAS Cougar joystick/throttle
Latest 3DMark2001 SE = 14,230
Good luck and have a good flight.