I think I figured out what the problem was. I removed all the computercraft computers, saved, then restarted the server. I had absolutely no lag. The cpu usage on the server went down to 4%-12%. Players and mobs are no longer jumping around. I'll keep playing with it to make sure.
Server Specs:
Pentium(R) Dual-Core CPU E5300 @ 2.60GHz, 2600 Mhz, 2 Core(s), 2 Logical Processor(s)
Installed Physical Memory (RAM) 8.00 GB
Size 74.19 GB (79,657,168,896 bytes) (SSD)
Free Space 46.94 GB (50,403,708,928 bytes)