Motion is very dependent on the graphics card. So you will need a machine with one of the following graphics cards:
ATI Radeon X800 XT Mac Edition
ATI Radeon 9800 XT (R360)
ATI Radeon 9800 Pro (R350)
ATI Radeon 9700 Pro (R300)
ATI Radeon 9600 XT (RV360)
ATI Radeon 9600 Pro (RV350)
ATI Mobility Radeon 9700 (RV M11)
ATI Mobility Radeon 9600 (RV M100
NVIDIA GeForce 6800 Ultra DDL (NV40)
NVIDIA GeForce Go5200 (NV34M)
NVIDIA GeForce FX 5200 Ultra (NV34)
NVIDIA GeForce 6800 GT DDL
If there is some kind of hack to get it to run, it would be very slow & tiresome to use.
I had to get a G5 to run motion as my G4 wasnt up to it.