Hi,

Maybe its a good start to explain wich computers you have, what graphics cards etc etc...
In my experience you can upgrade to V4 from V3 with both G5's and MACPRO's... Depending on what you want to do with V4 you may need to upgrade hardware as well..

You just have to buy an upgrade from Richard to transform from V3 to V4. Your dongle has to be updated also... But this can be done from within the catalyst software. You order the upgrade kit and receive a special code to reprogram your dongles...

V4 dongles will work with V3 aswell...