Luke, which IPAM version do you use? The performance of the IPAM_spTouchGroupCounts stored procedure was significantly improved in IPAM 3.0 which was released few weeks ago. If this is the version you use, please send me a personal message here on thwack. We would like to investigate this issue further, but first we need more information about your environment.
Thanks for the info.
I was running 2.0.1. You are correct regarding version 3.0's performance increase on this stored procedure, we've noticed a very significant speed increase when making changes to nodes in long chains of nested subnets. It's gone from 10-20 seconds to around 2-3.