"Matrox Graphics, Inc. GPU Chipset User Interface. Not needed, can be disabled safely. May interfere with Terminal Services." systemexplorer.net/.../mtxhotplugservice.exe.html That may be the best answer you get.  It does not appear in the billions of pages Google has access to that anyone has ever felt the need to try (or at least to document it), so since the purpose of that process is not documented by Matrox (or Microsoft, as it appears they may also use it for native Windows drivers for Matrox devices), the only way one would know is to try.  Since no one has tried, I would recommend you try it and document the results here :)  Worst case scenario:  killing it causes some [probably video] issue, in which case rebooting should restore you to normal operation.
There is a process on Windows 2008 R2 on R210 called MTXHOTPLUGSERVICE.EXE. I understand is something to do with Matrox video. However hot plug service in the name makes me think - do I really need it? I am using the box remotely through RDP and I dont need to hot plug anything so far. Can I disable it ?
Can I kill MTXHOTPLUGSERVICE.EXE on my R210?