MK14 VDU Modules Bench-marking

[Realtime]

In developing programs for MK14 I've realised there can be quite a performance difference depending which VDU solution is connected. To that end I've been bench-marking the VDU modules using a test version of Invaders that removes the game delays and toggles FLAG0 each game cycle. I've used invaders as I wanted something with a program cycle much longer than the VDU frame time (and hence much larger than the NENIN interrupt time). This results in 2 benchmark timings as shown in the photo.

I've made measurements for the VDU solutions I have access to and Coolsnaz2 kindly ran the benchmark on his original SoC VDU. In all cases, the MK14 has a 4MHz crystal installed.

                       Burst      Cycle   Performance  
VDU variant            time       time   (SoC/Variant)  Comment
=====================================================================================================================================
SoC VDU Card           10.8ms     129ms       1.0       This is the standard against which all others are compared
RealView (PAL)          7.8ms      98ms       1.3       Looks like I reduced the NENIN interupt time on this one
RealView (VGA)          9.4ms     112ms       1.1       Blanking period is shorter than for PAL, reducing its performance
PiView                  3.9ms      45ms       2.8       !! There is hardly any NENIN activity so the processor runs almost full speed    
OrtonView               TBA
P.E. VDU                TBA
Chris Oddy Replica      TBA
Others ?????   

(Note all timings have been averaged over a few readings)

I'm looking for volunteers to provide figures for those marked TBA and any others that I've missed. Attached is the hex file for Invaders2Test, which does require the full extension RAM (0x200-0x7FF). If you are able to provide a benchmark measurement please indicate if the MK14 has something other than a 4MHz crystal fitted.

The main drive behind this is to be able to include specific delays in games so that the game performance could be made broadly the same across all VDU module variants (plus it's just interesting to know!)

Thanks in advance