Suggested Upgrades for my Early 2009 Mac Pro (Primarily for Editing 4K Video)

Hello everyone, I'm gathering the parts necessary to upgrade my Mac Pro and I'm looking for some input on my part selection.The specific machine in question is my Early 2009 Mac Pro with its original BTO Configuration consisting of one 2.93GHz Quad Core Xeon, 8GB of RAM, 640GB Hard Drive, and an ATI Radeon HD 4870 with 512MB of VRAM. My machine handles 1080p editing fine, but I want to step up to editing 4K video now that I have a DJI Inspire 1 with its 4K Zenmuse X3 Camera. I also don't want to spend the money on one of the new "trashcan" Mac Pros because I don't see the reason to buy a machine that is not easily upgradable or repairable, plus I'm just not in the position to afford one right now.

Software I Use: For editing, I currently use Final Cut Pro X and Adobe Premiere Pro CC, both on the latest versions. Along with those two main programs, I also use Motion 5 and Adobe After Effects CC. Also, I also do a lot of work in Adobe Photoshop CC and Adobe Lightroom CC (I understand that these two programs are not nearly as resource intensive as FCPX and PPCC), along with music production in Logic Pro X (On a typical day, I'm working with around 60 tracks with many plugins running). Every now and then, I run a few VMs in VirtualBox to test out software updates to help check on critical software for my parents' businesses before I deploy them. Finally, I'm a gamer (Only on the weekends when my schoolwork and job stuff is taken care of 😉), so I'll be booting into Windows 10 via BootCamp to scratch my gaming itch.

Processor (Already Ordered): As stated above, my Mac Pro came BTO from the factory with a 2.93GHz Quad Core "Nehalem" Xeon (Model W3540, Turbo Boosts up to 3.2GHz). I'm planning on swapping it with a 3.2GHz Six Core Xeon (Model W3670, Turbo Boosts up to 3.46GHz) when it arrives. I chose the W3670 because of its Six Cores and 12 Threads, plus it was only $125 brand new in retail packaging on eBay. I considered a W3680 (3.33GHz Six Core, the one Apple put in the Six Core 5,1 models), and even a W3690 (3.46GHz Six Core, Turbo Boost to 3.73GHz) but decided against them because they were $100 and $200 more than the W3670 with only a 15% performance increase on the W3690 vs W3670. I know a Dual Socket Mac Pro would have been a better investment, but I didn't want to deal with the Deluded Xeons. Also, I know about all the Firmware Update jazz.

RAM: This is where my main question arises. My Mac Pro handles editing 1080p video just fine with 8GB, but I'm sure I'll need more for 4K. I'm considering 32GB of DDR3 ECC 1066MHz Memory from OWC (The W3670 is a Six Core, but still uses the slightly slower DDR3 1066MHz RAM compared to the W3680 and W3690), which would be installed as four 8GB DIMMs for $177.00. I've also considered 24GB because of it's lower cost at $137.99 and because the Mac Pro is supposed to work best in when RAM in installed in a Triple Channel configuration. Any input on this would be much appreciated.

Storage: Here is where I think the main weak link of speed in my Mac Pro is, the Hard Drive. it still has its original 640GB Hard Drive from the factory, and is still chugging along. For my upgrade, I was thinking of a pair of 480GB SSDs from OWC (That's give me 240GB for OS X and 240GB for Windows, enough for the OSs along with my applications and whatever current projects I'm working on). I understand that the SATA Ports on the Mac Pro's Backplane Board are limited to SATA II (3GB/s) speeds, so was wondering if its worth it to spend the extra money and get the OWC Mercury Extreme Pro 6G, and if I'd see any difference between a 6GB/s SSD connected at 3GB/s. I've also looked at the OWC Mercury Accelsior E2 because of its near "trashcan" Mac Pro speeds, but have already ruled this out due to pricing and not being able to install Windows via BootCamp because the Mac will see it as "External Storage". I'd also like to mention that I'd be running the drives in RAID 1 so I have an identical backup. I know that RAID 1 isn't the fastest option, but I want the redundancy. For mass storage, I'll probably go with a pair of 4TB HGST DeskStar NAS 7200RPM Hard Drives, I've seen these drives for as low as $139.99 on Newegg, which is quite possibly the best deal for a 4TB Hard Drive. Just like the SSDs, these would be put in RAID 1 for redundancy, and would be formatted into two 2TB Partitions for OS X and Windows respectively. Again, input is appreciated.

Graphics: This is where I believe the second weakest link in my Mac Pro chain is: the video card. More specifically, my Radeon HD 4870's paltry 512MB of VRAM. I am a gamer, and have an older PC that I built for gaming, but want to pass it on to a family member so he'll be happy and I'll have one machine that does it all. Anyway, I was looking at getting a NVIDIA GeForce GTX 980 Ti (Probably from EVGA because I've had zero issues with them, and their customer care is really good), due to CUDA Acceleration and because (I'll be the first to admit) I prefer NVIDIA over AMD from personal experience. Also, I'd like to avoid SLI like the plague if possible. I've been looking at it's benchmarks and am very impressed with its performance, but I'm worried about the power draw. From my research, I was able to confirm that the Mac Pro can deliver up to 225 Watts to whatever GPU is installed (75 Watts from the PCI-E Slot and 150 Watts total from the two 6 Pin PCI-E Cables). On the benchmarks, many show the 980 Ti peaking at around 250 Watts under full load (254 Watts was the highest I've seen), and every one I've seen always requires one 6 Pin and one 8 Pin PCI-E Power. I've also considered a traditional GeForce GTX 980 that requires two 6 Pin PCI-E Cables, but it's performance at 2560x1440p is more in line with a GTX 970. I know about the lack of an Apple Boot Screen, and that the GPU may run at PCI-E Gen 1 speed. My question is, is it worth the risk to install a GTX 980 Ti with one 6 Pin and one 8 Pin? I've seen cables online that go from the Mac Pro's Mini 6 Pin to traditional 8 Pin. Also, would you recommend a traditional "Blower Style" Cooler like on the Radeon HD 4870, or a cooler like EVGA's ACX 2.0 (I don't remember what the general term for these kinds of coolers are). Finally, could the GTX 980 Ti be Underclocked, or told to Underclock if the power draw hit 225 Watts? Finally, would you recommend having the new GPU Flashed by MacVidCards so I can get the Apple Boot Menu and have it run at PCI-E Gen 2 speeds? The pricing for that is $180.00. I'd also like to quickly mention that I do have a USB 3.0 Expansion Card and a BlackMagic DeckLink installed because I'm on the topic of PCI-E Expansion. This is where I'll really appreciate the help.

Conclusion: I'm looking to upgrade my aging Early 2009 Mac Pro so I can get more years out of it. I'll probably have about $1,250 total put into the upgrades when done. But like I said, its still cheaper than a new "trashcan" Mac Pro, and that's not even counting all the external adapters and enclosures I'd need to transfer my components from me beloved "cheesegrater". Any help with part selection is really appreciated.