The DMAFromPC operator does only exist for "pretty old" VD1 frame grabbers.
mE5 marathon/ironman is not supporting this operator for co-processor functionality.
While the DMA approach could potentially support GB/s in the downstream (Host-PC-Memory to Grabber) there is a non DMA way to upload images with around 10 MB/s using an alternative register interface instead of DMA.
What data-rates do you expect for your application?
I know that 10 MB/s is pretty limited.