Well if you’re convinced you have to have a nMP, so be it, however:
I’ve got a 2010 cMP (v 5.1). I’ve done several upgrades to it:
Boot drive replaced with a 1TB Samsung EVO950
Both 4 core 2.4 GHz Xeons replaced with 6 core 3.46 GHz Xeons
Stock Video card moved to slot 4
Upgraded ram from stock 1033 to 24 GB (3x8GB) 1333 Registered DDR.
Added a pair of GTX 970’s in slots 1 & 2 (without needing an additional power supply).
As a result for less than 1/4 the price of a bare bones nMP, I have a very flexible machine that outperforms a brand new nMP on several fronts:
It’s 20% faster for baseline CPU based work (i.e. Rhino)
It’s 70% faster than a nMP for rendering via Cycles in Blender (the nMPS use ATI cards, and they are not so good for most video production / 3D production work. You really want CUDA support if you’re doing anything in AE, Final Cut Pro, Davinci Resolve. You’re going to pay a pretty steep performance hit using open CL for those apps.
They aren’t nearly as expandable. If you want to bump up the drive capacity you have to go external. If you want more RAM, good luck with that, as you have to use some VERY expensive ram ($236 / 16GB stick vs $140, and you don’t have nearly the number of slots to use, so you can’t economize by using say 8GB or 4GB sticks to get the same amount of installed ram).
Adding additional video cards is impossible. The D700’s are already obsolete, and very easily outperformed by any number of other video cards on the market that are very cost effective. There’s simply little to no upgrade path in the GPU front without doing some fairly extreme hardware hacking. With a cMP you can buy pretty much any NVIDIA based card, install NVIDIA’s drivers and be good to go. IF you really must have a mac based EFI because you want to see the full boot screen, MacVidCards can flash the PC based cards for you for the vast majority of the NVIDIA cards out there (including the Titan X, which stomps the ATI cards into the ground and then some).
If you need to get into 4K video, it will be decidedly problematic as the ATI’s don’t handle multi steam format well at all so you’ll be stuck at 30Hz which on a 4K display is horrid. Other option would be to buy a single stream 4K display which will cost (currently) about 3-4X as much.
I’m not dissing the nMP on general principals. I’ve been a mac guy since the original Mac SE and have owned more models than I can count since the mid 80’s. However, the nMP is probably the worst bang for the buck and least expandible / upgradable model ever produced for professional use. It looks spiffy as hell, but it’s pretty much a dead end box.
However if you’re really convinced you just have to have the trashcan and don’t mind paying a 2-4 times more than you have to do get less performance, have at it.