ATI Radeon HD 4200 not working properly

What driver are you using? How can you tll only 256MB are recognized?

On Windows it is using shared memory .. there aint no 700MB card. It can be (old ones: 8MB, 16MB, 32MB, 64MB etc..) 256MB, 512MB 1GB etc..

Well how do I set up shared memory on Linux?

*Ubuntu

ATI Radeon HD 4200 is an integrated graphics processor. The amount of video RAM is set up in the BIOS.
Windows might tell 700 MB because it subtacts total RAM and available RAM, but that is an innaccurate method, specially in 32 bit windows.
Linux might say 256MB because it the maximum memory you can address through the PCI bus, but current Ubuntu ships with a radeon drived that can handle 512 MB RAM.

So look in the bios setup how much shared video memory you have and if yo are using ubuntu 10.04 then you are using all of it.

In bios I have 256 mb set up for my vram but Windows picks it up as 700 and it gets much better performance on windows. Any way to improve my video performance on Ubuntu without using more shared memory or buying a new vid card? Cuz I only have 2 gb of ram and I'm saving to get a whole new pc, not improve this one.

The 700MB reported by Windows are plain wrong.

Ya but I want the same performance I get on windows. On Ubuntu I can hardly run Oblivion. On windows I can play Far Cry 2 at decent quality

The open 3D drivers' performance will be better in the next Ubuntu release. 10.04 is the first release with ATI open drivers that support 3D.
Try the ATI catalyst drivers if you want.

I tried the ATI Catalyst Driver and had the same problem. THE CARD WAS UNABLE TO DO ANY GAMING!!!!