No nxproxy. Just nxagent and nxnode, with nxnode using less than a meg of res - shared.
For X, most of that "resident" is resident *video ram*, often mapped multiple times, and not system RAM. X servers always look like they are using a lot more system than they really are.
At any rate, when we switched from VNC to NX, I recall that the reduction in memory use was clearly discernable in the systat reports. Note that the 34MB for the Xvnc process represents 3.4GB with a hundred desktops running. When people tell me that program Q "only" consumes 34MB, I automatically multiply by 70 to see what the *real* consumption would be if my users were running it on my most heavily loaded server. It makes a difference.