I noticed that dual core works really well. But than again I have not had any issues like you mentioned. I successfully ran 3CX on a laptop 500hz and less than 1gb, mind you not many calls in and out but for small business can do (not recommended, but I like to disagree with you where I can (LOL)). Best performance I got was on: 900Mhz dual P. with 2GB or more, having 3CX and OS on separate disks and using SBS. It goes without saying that the better the specs the better the performance, but what is interesting to see is that there is not much of a CPU utilization using 3CX. It runs now on a DUal Core 2.5, with 2gb and SBS it runs like a dream, cristal clear etc, this box has several other applications on it including our in house Sharepoint server and Music and Video collection streaming (internal only). Network config is important as well, although voice traffic does not use the full 100mb bandwidth we noticed since we uprated to our Giga lan the IPPhone traffic is alot better. It all adds up I guess H.