One interesting side note that on average the Intel Core i7 920 CPU usage was noticeably higher (double or more) when using a NVIDIA graphics card and its proprietary driver compared to AMD's Catalyst driver.
If you are a Linux gamer, as you can see from these OpenGL test results there really isn't that much you can expect from the Radeon HD 5450. Even those on a tight budget would be much better off buying a graphics card for $60 USD or more like the NVIDIA GeForce GT 220 that is much more capable, but still you would be left disappointed if wanting to run any Unigine-based games. If you are just a normal desktop user, the Radeon HD 5450 would be sufficient and it can at least handle running a compositing manager just fine. There is also video playback acceleration via XvBA (the X-Video Bitstream Acceleration) architecture, but that is currently buggy in the latest driver revisions and overall has been a messy implementation with it only being exposed through the VA-API front-end. Anyone interested in a low-power, passively-cooled graphics card for a HTPC / media PC still would be much better off getting any NVIDIA graphics card that has PureVideo HD (even the ~$30 USD graphics cards) as with VDPAU (the Video Decode and Presentation API for Unix) you'll be left with a much better and more pleasant experience. If you are just interested in supporting AMD for their open-source efforts, this is a fine card but obviously with even the proprietary Catalyst driver producing low frame-rates, do not expect much at all out of any Mesa / Gallium3D driver for Evergreen on the Cedar GPU. For anyone interested, the Sapphire Radeon HD 5450 can be found at NewEgg and Amazon.