With no other viable options at the time, I made the following upgrades to a 2010 Mac Pro (5,1) about two years ago - primarily for rendering with VRay. VRay uses CUDA, so the AMD GPUs of the trashcan Mac were of little use and adding Thunderbolt chassis for external GPUs would have just added to the cost. So here are the parts and costs - since then prices have come down on a number of these components, so the costs would be even better for the comparisons: 2010 Mac Pro $1900 512Gb SSD $230 (3) 4Tb Hard Drives $315 64Gb RAM $320 Sonnet Tango 3.0 $80 (2) GeForce GTX 680 GPUs $1240 (2) Intel Xeon X5690 $500 Thermaltake V1 Chassis $30 EVGA 750W PSU $113 PSU Daisy Chain Adapter $21 GPU Power Leads $104 Total $4853 For comparison, a 2013 Mac Pro (6,1) with 12- core 2.7Ghz processor, 64Gb RAM, 512Gb SSD, and AMD FirePro D500 GPUs lists for $6400 – despite being unchanged in over four years. From there, I would still have had to add the additional hard drives ($315), Nvidia GPUs ($1240), and cases for both the drives ($430 - 4-bay RAID) and GPUs ($450 - 2-slot PCIe Expansion Chassis) for a grand total of $8835 – nearly twice the price of my system build. Apple released the iMac Pro since my build (12/17). Although it offers options of 8 to 18 cores and up to 128Gb of RAM, it still only offers two (proprietary) AMD graphics options and only 1, 2, and 4Tb SSD options for storage with a price of $5000 to nearly $13,500 fully optioned. To price a somewhat comparable system, I chose the 3.0Ghz 10-core processor, 64Gb RAM, 1Tb SSD, and Radeon Pro Vega 56 graphics for a price of $6600. However, similar to the 2013 Mac Pro, I would still be faced with costs for additional drives, GPUs, and enclosures for a grand total of $9035. It would have gained me some speed, double the space on my boot SSD, and saved me the $290.00 cost of one 27” monitor, though (bringing the price down to $8745 and beating the Mac Pro). For the most part, the build was plug-and-play including the processor upgrades. A hex wrench, cleaner, thermal paste, and some careful work were all the tools that were required to swap the processors. However, to power the two GTX 680 cards, I added an external chassis for the 750W PSU controlled by the Daisy Chain Adapter and running the power leads back into the rear of the Mac Pro case. Others have stuffed PSUs into the optical drive bays or made other modifications, but this route seemed to be that of least resistance to me. With the rendering use, the two cards offers better distribution than a single faster card although I'd be interested in comparing it to what is available now. Although I have been looking at options to further upgrade the graphics cards, the current premiums caused by the bitcoin situation has that on hold until prices potentially stabilize. I will also likely paint the accessory power chassis to match the Mac Pro tower. So here are some images of the final product.