Thanks for the reply Mike. The new server will have 32Gb of RAM and solid state drives. I've tried to answer to questions below.
1. How many ACT! users? 30
2. How many other users running services on the server? Still not sure.
3. SBS has Exchange, which can such all the RAM and cause performance issues in ACT!
4. Web, Lan share, sync, mobile access? Not sure.
5. How big is the ADF in GB? 0.98 Gb
7. How many files in Attachments folder (size doesn't matter)? Is there a default location?
Level 1 Support Technician