That "uh,uhuh" was a Jurrassic Park reference I'm pretty sure that the fatman used to protect his SGI boxen.
VNC has to bind to a specific X interface (:0 by default usually), but especially in the "old days" there was a lot of overhead because it was multi-platform. If you terminal in (turn off encryption in a local environment, those RISC rs/6k's machines didn't have any hardware-offloaded encryption so you're wasting tons of cycles) with something like -- ssh -p 8400 -l username -X -v <ip> , then from that terminal, fire up an instance of which ever application. What will end up happening is that all of the X instructions will be passed (a way lower payload of data size-wise) to your own instance of X, which will suffer the "heavy brunt" of rendering/updates. It should be faster than in native.
There's still some silent tk love out there since what it was good at, it was really good at. (Just like there's a semi-healthy Delphi community still making VCLs since it was really good at making line of business applications). Modern GUI frameworks (QT5 + QtQuick + QML) and modern languages (C++11 has threads part of the standard, so that portability headache of win32 threads vs POSIX pthreads is taken care of) makes things a lot easier to write these days.
I haven't used this logic analyser myself but I know it was fast enough to develop PCI-e and do in-circuit non-invasive probing for Pentium 4's and Xeons (you had to max out all them expansion slots and get a specific FPGA aux component from Xilinx or someone, but it was possible). I'm sure there's a way to increase the DAQ such that 21 megabytes doesn't hurt