According to best practices, it is recommended to move all tempdb (not just tempdb) files into different physical disk.
I have a virtual server which had originally 4 LUNs from the same RAID 10 pool. By the help of volume manager, I converted those 4 LUNs into 4 different volumes.
Now the question is, will it make any difference by moving tempdb into separate volume, or it is just fine to keep them with other SQL Server files in terms of performance?