On the R310 we officially support and have tested and validated RHEL 4, 5, and 6; SLES 11, and XenServer 5.6 and 6. Ubuntu and derivatives have not gone through the testing/validation process by Dell however many have gotten it to work with little to no trouble, though I haven't heard of anyone running Kubuntu specifically. If you're booted into KDE/using the server as an interactive graphical workstation then I can imagine the desktop may seem a bit sluggish due to the minimal graphics capability of the server model. Are there specific areas where it seems slow to you? 64-bit would let you access all the RAM (as opposed to sharing the address space with I/O ports) though I don't imagine there would be a big performance difference between 32- and 64-bit except perhaps in specific applications that take advantage of 64-bit architecture.
Hi all,  I have an R310 with the Petium 6950 2.8Ghz cpu and 4GB RAM. Currently I am running Kubuntu 12.04.1 32bit OS.  It seems to run fine, just kinda sluggish. Does anyone know if it would be better to put 64bit on there? Or, is there a better version of Linux for the R310 servers? Any help would be appreciated.
Kubuntu on R310