A strain of short term lag problem.

I own both Quake 3 and Star Trek Voyager Elite Force. Along with a voodoo3 3000. The problem I have had only occured after I installed a maxis games called “The Sims” The problem is the game will run soomth for 3 minuets. And shortly after that the game will go into incredble lag just for 20 seconds. Then it would go back to soomth game play. Before I installed the Sim’s, my game play was always soomth. I have tried everything, unistalling the Sim’s, reinstalling the voodoo3, adjusting every possible setting on the two games. Nothing seems to be working. If any one has had this problem and some how corrected it. Please tell me how to do of so. Thanks for your time.