Hi johhny here on this forum you wont get any answers and if you do then you are in luck or the answer might be get cubix xpander 3k. But here what i did and its awesome.
The most important hardware component for smooth raw editing in Resolve is no longer the CPU. It is absolutely essential to get an NVidia graphics card, and a high end one. By high end I mean from the gamer / consumer line not the pro Quadro line which is somewhat outgunned for far less money by the gamer cards. NVidia have taken note of this and so there’s somewhat less performance improvement to be had from their latest GTX 6 series cards in CUDA. CUDA is a set of instructions which allows the brute force number crunching of the GPU to be used like a CPU programmable unit by software, not just 3D gaming. The older 5 series cards like the GTX 570 and 580 work superbly. They do however require more power and tend to have nosier fans. You may need to upgrade the PSU (power supply unit) of your PC if you opt for the most powerful 5 series cards. Most PCs have a mediocre 450 Watt PSU and ideally you need a high quality 600 Watt PSU for the GTX 580. Don’t just buy one based on wattage, is really is the quality of the power supply that matters as well.
The GTX 580 is double the price of the GTX 560 Ti which runs quietly and doesn’t require a more powerful than average watt PSU. However you can only get away with the most basic Resolve editing and grading with the cheaper card and it isn’t very future proof. It is better to opt for the GTX 580, 670 or 680.
With the latest GTX 670 and 680 cards you won’t see much of a performance increase over the 580, rather a reduction in power consumption and fan noise. The GTX 580 second hand will give you the most bang for buck when it comes to performance alone. The cards have various amounts of video memory from 1GB to 4GB. You can edit Blackmagic Cinema Camera raw with 1.25GB of video RAM but running Resolve and Premiere at the same time will require 3GB. For Red 4K raw 4GB is preferable.
I have ATI radon 5770 two gtx 660 4gb each with external power powering them all and i can edit 4k no problems.
BUT dont forget HD i have 2 1 gb black edition western digital in raid 0