Power Edge R300 storage maximum

I have a pair of R300 Power Edge servers and I want to max out the storage.  Since these machines are circa 2006, I was wondering if there are any limits to he maximum size hard drives than can be installed.  I have a pair of 1GB SATA drives in each machine now set up as a RAID 0 configuration and that works fine, but I need storage capacity more than speed at the moment, so I was thinking 4TB hard drives will solve that demand.  What is the maximum size for the R300  PE Server for chassis (internal) mounted SATA hard drive storage?  Thanks in advance..