according to device-id of imac's 4850- 944A, its mobility version(http://www.x.org/wiki/Radeon ASICs) , it has full 800 SP, but lower clocks than desktop version.
3dmark06 highly depends on cpu, better compare 3dmark vantage gpu scores.
darkgoob, xbench is ancient, comparing anything with it worth nothing.
to compare graphics, you can use glview, http://www.realtech-vr.com/glview/download.html
need to set highest available settings for test, like 16xAF, 8xAA, check benchmark option, and if cpu load isnt 100%(load of one core, since opengl context is still single threaded) durring test, then it's not cpu bound. and benchmark results is comparable.
here is result of desktop 4850 (625/1000)
3dmark06 highly depends on cpu, better compare 3dmark vantage gpu scores.
darkgoob, xbench is ancient, comparing anything with it worth nothing.
to compare graphics, you can use glview, http://www.realtech-vr.com/glview/download.html
need to set highest available settings for test, like 16xAF, 8xAA, check benchmark option, and if cpu load isnt 100%(load of one core, since opengl context is still single threaded) durring test, then it's not cpu bound. and benchmark results is comparable.
here is result of desktop 4850 (625/1000)