The TeaTimer resource usage will depend on the user motivation and the amount of resources the computer has (RAM). By default when TeaTimer is first activated, it is set to "Conserve" memory mode, thus this tends to suit systems who have large memory amounts, say like 1 GB of memory. Of course, the user can (with a registry tweak) set it to run faster if they have the resources.
@snowboarder, you have to explain your situation a little more. Have you disabled "SDHelper" and see if that improves the situation? What is your current Internet Connection provided by your ISP (dial-up, DSL [broadband], Wi-Fi)?
Spybot-SD 1.6.0.30 is optimized for faster scanning time and Immunization for newer browsers such as Firefox 3.x and Opera 9.5.x. So yes, a shorter (faster) scanning time would be one of the benefits.
Also, hopeful and snowboarder, I would like you to open TaskManager and see how much memory TeaTimer is using.