Not a ram issue, a GMod issue that is probably exacerbated by our DarkRP server being mega-populated. I've been looking at reducing the amount of traffic our DRP servers sends to the clients, but to no avail as of right now.
I don't think computer memory has anything to do with network latency or any sort of network data being sent or received. however bandwith itself might be an issue. Overflows usually do happen when data is sent too fast. Also could be that the server is trying to catch up and is running so many ticks behind that the normal data you send becomes too much.