It is odd I'm getting wildly different results, my hd4600 is at 1.35ghz with 512mb of 1866 11 cas ram allocated to it. My glmark score is 245 and my qgears is 145 fps. Note I have qgears 1.0-1 and glmark 2012.12-2 from the AUR. Maybe the tests expect more vram? I've done periphery testing running at various ram allocations before and found my performance is most titles at 1080p peaks at 512.
I went looking around results on obm but the results are heavily diluted with old xservers, mesas, and kernels.