From almost the moment I installed LS 4 to the moment I stopped the LS service, the server was taxed at 100% CPU usage with process LSASS taking up about 85% - 90% and lansweeper taking up the rest. SQL server was taking up about 1.4GB of memory as well.
If I start the LS service again, CPU usage goes back up to 100% within 30 seconds of starting. It dips for a bit then sits at 100%. I'm assuming these 100% usages are happening when AD Scanning is going on.
I'm using Windows 2008 x64 (non-R2) with SQL Express 2005, one 2.3 GHZ single core CPU (server is a VM on vSphere), and 4 GB Memory. There are also 21 domains in our network and about ~3k workstations.
LS 3.5.2 would sometimes also tax the server at 100% but not constantly. LS 3.5.2 was running on the same hardware as above.
I'm now going to move the installation to a new VM running 2k3 R2 x86 with four 2.3 GHZ cores to see if that helps.