Need Desktop Capable of Downscaling & Rendering 4k footage into 1080 with Ease.

[BostinOriginals]

Hello all, I was hoping to avoid creating my own thread because I know there are already loads of Q&A out there. However, after several days I am still as uncertain as when I started. I need help knowing what to look for when it comes to a new computer. So I come to you fine people respectfully with open ears and a modest budget.

Current Situation
I am currently working with a Panasonic GH4 as I am shooting a small documentary away from home. I love the camera and am highly considering purchasing one for myself. However, I fear my "current" home PC setup is a bit outdated if I was to edit on it with the Gh4's 4k footage, as it was created as a gaming computer many years ago: Core 2 duo, 16gb DDR2, 2 Nvidia GeForce 7800 GT (SLI), Nforce 570 Slit-A board, running Windows XP.

Objective and Requirements
Okay so what I really plan on doing with the GH4 footage and my editing is taking the 4k footage and downscaling the UHD into 1080 HD. I have seen great image quality as a result of this process. I don't have a real desire to edit the 4k raw footage (down the road, eventually) mainly because no one really has 4k capable screens, I just want great quality 1080.

I have a medium sized budget of $1200, however will highly consider spending more for quality. Obviously this needs to be something capable, reliable, and expandable for future 4k editing when I get the money to throw into the setup. Again I really just want to downscale and render the 4k into 1080, and yes I am not entirely certain the minimum system requirements a task like this will require. I just assume my old PC (detailed above) will not handle it.

Research and Question
I have spent several days combing online forums, desktop reviews, and looked into parts to build one myself on. My real question I suppose is what is the minimum requirements to do such a task as downscaling UHD to HD with ease. Is it the same requirements as a system that is used to edit the 4k footage raw without downscaling?

Would something like the ASUS M70AD-US003S be good for such a task with room to expand?

Could I get away with something cheaper like the ASUS M51AC-US004S and spend money on a better GPU and RAM?

Or should I build my own?
Desired Budget = $1200
Maximum Budget = approx. $1600

Thoughts, Opinions, Solutions, and Recommendations on the best bang for your buck system capable of running smoothly while rendering 4k footage downscaled to 1080 are all welcome.

Note I do want a system capable of color corrections and after effects. Needs to last me a few years.

Thank you! -Bostin

 

[AMD Radeon]

if you build your own, it should be something like this (minimum)

XEON haswell, cheaper version of i7
256GB for OS and scratch disk
2x 2TB for multidrive rendering
rendering will bring the cpu to 100% all the time. need cpu cooler

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Xeon E3-1230 V3 3.3GHz Quad-Core Processor ($249.98 @ SuperBiiz)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.98 @ OutletPC)
Motherboard: ASRock H97 PRO4 ATX LGA1150 Motherboard ($76.66 @ Newegg)
Memory: Corsair Vengeance Pro 16GB (2 x 8GB) DDR3-1600 Memory ($144.99 @ Newegg)
Storage: Crucial MX100 256GB 2.5" Solid State Drive ($109.99 @ SuperBiiz)
Storage: Hitachi Deskstar 7K2000 2TB 3.5" 7200RPM Internal Hard Drive ($78.12 @ Amazon)
Storage: Hitachi Deskstar 7K2000 2TB 3.5" 7200RPM Internal Hard Drive ($78.12 @ Amazon)
Video Card: Asus GeForce GTX 750 Ti 2GB Video Card ($115.00 @ Newegg)
Case: Enermax ECA3253-BL ATX Mid Tower Case ($29.99 @ Newegg)
Power Supply: Rosewill Capstone 450W 80+ Gold Certified ATX Power Supply ($52.98 @ Newegg)
Optical Drive: LG GH24NSB0 DVD/CD Writer ($14.99 @ NCIX US)
Total: $980.80
Prices include shipping, taxes, and discounts when available