SG and HSO [two older urt clans] have found that attualy putting loads of high slots servers onto a single box does create a wierd laggy feel.
We HSO Have had, a Quad Core, Dual Core and Single Core Servers (as in dedicated boxes). But there is a single clear thing we found out. A Webserver hosting a website that is used (be is lightly) definatly makes any urt server on that box more laggy.
Also since the game is UDP the number of packets get blasted at the server increases the chance that a few are lost or delayed. The more slots and the more servers that are piled in start to make this effect worse. Obviously its not cost effective, but the BEST possible hosting of a UrT Game Server has to be on its own server, then its the best it can be. HSO Now use cheep Single core servers 2.8Ghz Each with 2G of memory to host a Single Public and Single Private Game Server, we found the results amasing.
IIRC the servers are on a multi-core machine?
maybe make a try and assign the bomb and the tdm server each to a single core could help on improving?
if they are not, forget about this post
source: http://forums.urbanterror.net/index.php/topic,16361.msg224147.html#msg224147