Resolume Forum

dxv, and dxv3 are decoded by your gpu with resolume (4.2+ for dxv3)
all other formats are decoded by your cpu.

I took a look at the benchmark results, firepro d700 has much higher scores under windows on a mac pro, so it could be buggy osx drivers.
on osx it had a 10 layer1080p noise performance, so if you can play 2-3 4k dxv layers that would be consistent with that result.
I can play 8 layers noise 1080 on osx and 1-2 layers 4k on my 2012 macbook pro.
windows performance is much better for me too.

I think, your results seem consistent with my benchmark results:

On my mid 2014 MBP, I can up to four 4K layers: viewtopic.php?f=11&t=11093&hilit=benchmark#p49135

but on my PC desktop with GTX980, I can play up to fifteen 4K layers: viewtopic.php?f=11&t=11093&hilit=benchmark#p49166

Have you tried to Syphon Arena to MadMapper 2.0 yet? Mad mapper is 64bit and should support all outputs.
Thanks in advance.
I may pick up a macPro;)