rsync using a lot of memory at receiving end (receiving end is cPanel ssh login)

[Chris Green]

I have been using rsync to copy some web site files to a new (to me)
hosting platform.  Yesterday I was doing this and noticed that my ssh
login to cPanel in another terminal window was unresponsive.

On looking at the browser display of my cPanel admin window I saw that
the 'Physical Memory Usage' was banging up against my limit of 1Gb.
No other limits are being reached at all, at most there's 4 or 5
processes running, CPU load and I/O use is negligable.

I'm running rsync  version 3.0.9  protocol version 30 and the cPanel
receiving end is rsync  version 3.0.9  protocol version 30.

Is this to be expected (using so much memory) or is something going
wrong somewhere?  More to the point is there anything I can do about
it? 
-- 
Chris Green