rolli59 :
Not very well. I suggest a minimum of HD4350 or HD5450 graphics card to do that.
and in all reality, the onboard HD3200/3300/4200/4290 will help play back these files just fine (also the NV IGP's work just as good)
the X4500 doesn't do so good, but the IGP in the new i3/i5's do a decent job