Graphics Card (GPU) render engines such as Redhift3D, Octane or VRAY-RT have matured quite a bit over the last years and are starting to overtake CPU-based Render-Engines.
But what hardware gives the best-bang-for-the-buck and what do you have to keep in mind when building your GPU-Workstation? The best Hardware and best GPU for rendering that is affordable?
Since GPU-Render Engines use the GPU to render, technically you should go for a max-core-clock CPU like the Intel i7 7700K that clocks at 4,2GHz. That said though, there is another factor to consider when choosing a CPU: PCIE-Lanes. GPUs are attached to the CPU via PCIE-Lanes on the motherboard. Different CPUs support different amounts of PCIE-Lanes and Top-tier GPUs run on 16x PCIE 3.0 Lanes.
The i7 7700K has 16 PCIE-Lanes meaning you could just use one GPU at full speed with this CPU. If you want more GPUs you would need a different CPU that supports more PCIE-Lanes like the i7 6800K (28 PCIE-Lanes) or the i7 6850K (40 PCIE-Lanes).
GPUs though can also run in lower speed modes such as 8x PCIE 3.0 Speeds and then also use up less PCIE-Lanes (8x). Usually there is a negligible difference in Rendering Speed when having GPUs run in 8x mode instead of 16x mode. This would mean you could run 2x GPUs on an i7 7700K in 8x PCIE mode, 3x GPUs on an i7 6800K and 5x GPUs on an i7 6850K.
To use Octane and Redshift you will need a GPU that has CUDA-Cores, meaning you will need a NVIDIA GPU. VRAY-RT additionally supports openCL meaning you could use an AMD card here.
The best bang-for-the-buck NVIDIA cards are 1070 GTX (1920 Cuda Cores, 8GB VRAM), 1080 GTX (2560 Cuda Cores, 8GB VRAM) and the 1080 Ti (3584 Cuda Cores, 11GB VRAM).
Founders Edition Blower Style Cooler
- PRO: Better Cooling when stacking more than one card
- CON: Louder than Custom Partner Card Cooling
Custom Partner Cooling
- PRO: Quieter than Blower Style, Cheaper
- CON: Worse Cooling when stacking cards
- PRO: Best All-In-One Cooling for stacking cards
- CON: More Expensive, needs room for radiators in Case
- PRO: Best temps when stacking cards, Quiet
- CON: Needs lots of extra room in the case for tank and radiators, More Expensive
Be sure to get a strong enough Power supply for your system. Most Cards have a TDP of around 180-250W. CPU of around 100W and any additional Hardware in your case.
I Recommend a 500W for a One-GPU-Build. Add 250W for every additional GPU.
Make sure the Mainboard has the desired amount of PCIE-Lanes and does not share Lanes with Sata or M.2 slots. Obviously you’ll need a 1151 type Socket for a Kaby Lake i7 (e.g. 7700K) type CPU and a 2011-3 Socket Mainboard for a Broadwell-E type i7 CPU (6800K, 6850K, 6950X).