Ram

just got a powermac quick silver 867 mhz with 1.2 gigs of ram...i want to know if there is anything i could do to make it run less laggy when multiple programs are running?....i could only max it at 1.5 gb of ram so i doubt an extra 256 will show a great difference, but i just would like to run a little smoother, any ideas?

What OS is the machine running and do you use a cleaning utility such as Onyx?

its running leopard, i dont use a cleaning utility no, could it be the video card?
it wont play back videos with out it being choppy

Being a Quicksilver probably has a nVidia GeForce 2/4MX or similar video card and could certainly do with say a flashed GeForce 6200 with 256MB VRAM to handle Leopard as the original card will not be Quartz or Core Image capable and remember your machine is at the very minimum of Leopard's specs.

First off I would download a utility called Onyx and run that and see if there is any noticeable difference before spending your money.