From Fedora Project Wiki
- [tbzatek] What is the minimum CPU required to have reasonable performance? Will we limit gnome-shell animations for slower CPUs?
- [ajax] "Minimum" is handwavey. It really depends on your pain tolerance and the size of your display, but (for example) CPUs without SSE2 are probably going to be unusable. It is expected that the shell will disable shadows and reduce animations in this mode.
- [jreiser] See Notable IA-32 CPUs not supporting SSE2 in [1]. I believe that performance will be disappointing on a box that had a "mid-life" upgrade to a graphics card that is less than ATI R300 or equivalent [2]. If an upgraded card runs in fallback mode today, then the original CPU likely will be too slow for good performance with the new software driver. For example: ATI 9250 (RV280, still new 6 years ago) on 1.6GHz Pentium 4 Northwood (new 9.5 years ago). The CPU has SSE2, the combo runs Fedora 14 just fine and under WinXP plays old games well and newer games OK, but Gnome shell uses fallback mode under Fedora 15. Also, a major impetus for CPU virtualization is to achieve lower cost via higher real CPU utilization in a virtual cluster. I am wary of contention for the CPU in such an environment.