Sage 2010 Accounts going slow

I am getting massive CPU usage and long delays when Sage on my computer accesses across the LAN to Sage on my other computer. The delays and excess cpu usage can be avoided by turning off the virus checker. I understand that I need to give Avast pro a correct exclusion list,so I contacted Sage and they gave me a long list of filetypes which I have entered, but the problem remains the same. The program has become almost unusable, cananybody please advise me.

We updated to Sage Accounts 2010 and within 3 days the system had slowed down making invoicing and data checking a total nightmare. Sage have been unable to resolve the issue blaming it on our server and network, however all our other software is working fine.