Application Metering Resource Hog?

I just wanted general feedback on whether implementing Application Metering in SMP 7.5 will be a huge resource hit on the clients.  We still have old P4 boxes out there and a decent amount of Core i3 NUCs as well so don't want to go killing these slower workstations with App Metering.  Not sure how much the product has matured from the Altiris 6 days so thought I'd ask the community for your personal opinions.  Thanks in advance!