For those wondering how much video memory you should allocate from your system RAM for the Radeon R3 Graphics with the new AM1 APUs, we have up some new Linux OpenGL benchmarks of the AMD Athlon 5350 performance with varying amounts of video memory available.
Through the UEFI system BIOS area for the ASRock AM1H-ITX motherboard we are able to adjust the amount of video memory available to the integrated graphics processor of the Kabini APU. Most AM1 motherboards offer this option and in general it defaults to around 512MB of video RAM that's made available.
These benchmarks this Easter weekend are just doing some tests with 256MB, 512MB, 1024MB, and 2048MB of system memory allocated to the graphics. The ASRock motherboard allows allocating as little as 32MB of video memory, but when pushing for 128MB or less, Ubuntu's Unity desktop wouldn't even start-up. The point of this testing is mainly to look at the Linux driver's performance impact when under memory pressure and using the Catalyst binary blob.