MSI FX5900-TD or MSI FX5700 Ultra Need Help

Question

What card is the better one to buy and why?
My Mainboard MSI K7N2 Delta-ILSR(601-6570-030)
2X 512mb DDR 3200 Crucial memory
AMD 2800+ 333 mhz FSB Boxed AXDA2800DKV4D Y822396250958 AQXEA 0318MPMW
1999 AMD Barton (or though it says nothing on the box about being a Barton and having 512kb L2 Cache) is there any way to tell what it is? If it is can the bus be overclocked to 200 FSB ok?
CPU Fan Cooler Master Aero 7 Lite (CP5-8J71F) is this fan ok or would I be best using the one that came with the CPU?
Graphics Card ???
Almost built.
The MSI FX5900-TD 128mb
Product Specifications
Graphics Core: 256-bit
Memory Interface: 256-bit
Memory Bandwidth: 27.2GB/sec.
Fill Rate: 3.6 billion texels/sec.
Vertices per Second: 338 million
Memory Data Rate: 850MHz
Pixels per Clock (peak): 8
Textures per Pixel: 16
RAMDACs: 400MHz
or
The MSI FX5700 Ultra
Product Specifications
256-bit
Memory Interface: 128-bit
Memory Bandwidth: 14.4GB/sec.
Fill Rate: 1.9 billion pixels/sec.
Vertices/sec. 356 million
Memory Data Rate: 900 MHz
Pixels per Clock (peak): 4
Textures per Pixel: 16
RAMDACs 400 MHz
Thanks for any help!  

Answer 1

The 256 MB version will allow you to load heavier 3D scenes in its memory with great performance, but the 128 MB version will have more bandwidth and it will generally be faster, although when the time come that a 128 MB video card will run out of memory, then the card will start to swap memory between its memory and AGP memory, thus it will be much slower that having a 256 MB version a bit slower.
Confused?
I´d go for the 256 MB version. although it has 2.8 Ns memory and you could reach just 714 MHz memory clock speed, but the other card will have less memory.
It´s just an opinion, but I would choose 256 MB version if I were you, and if I had the money