how many memory cost per connection?

[李安安]

Hi,
   I use guacd and connect ssh/telnet/vnc/rdp devices.
   Previously testing a connection cost about 150m of memory(test 1600 
connection use 92% of 256g).
   Half a year later. Now testing a connection costs 40m of memory(test 220 
connection use 8g). Test many times.
   The system doesn't change. What could be the reason for this?
   Also, how much memory does a connection theoretically consume?
  Thank you for helping me with my questions

Thanks～