I was running build 4128 on a WinXP Pro machine and the system worked without any problems. I recently got hold of a Windows Vista HOME Premium machine (edit by 3CX - not supported by 3Cx, Pro is required) and decided that I wanted to move the PBX over to that machine. I am able to install both builds, 4128 and 4393, (I tried the old build to see if the I was having the same problem after uninstalling the new build which is the case). The system appears to work and I can add extensions and make calls with either of the two builds. My concern is that after the install on the Vista HOME Premium machine (edit by 3CX - not supported by 3Cx, Pro is required) box, the 3cxMediaServer service becomes a CPU hog averaging 60+ percent of the CPU continuously. The memory is controlled fluctuating between 20 and 50 MB. The memory is not my concern. The 3cxMediaServer service does not exhibit this behavior on the WinXP machine. The high CPU usage does not seem to affect other programs but does cause the "Line Status" and "Server Status" pages with the 3cx web interface to load and refresh extremely slow. We're talking 2+ minutes for those screens to refresh. The other features like "General Settings", "Add/Manage extensions" ,"Add VOIP Provider" all work at regular speed. None of the other 3cx services are acting up. Just the MediaServer service. The windows vista machine is Vista SP1 2.4 AMD 512K L2 Cache 1 GB DDR2 Ram 160 GB STAII HD with 70% free space What I'm left with is a working system that uses too much CPU. I can't have my box ticking away like that when there isn't even a registered device. Is this normal? Anyone else having this problem on Vista? Other things I do have Skype installed I do have ORB server installed I do have 3cx Soft phone installed. Any suggestions?