Like most applications, there is a page describing the system requirements for Arnold on the official Solid Angle website. However, this page is extremely bare: it lists the supported operating systems and specifies a required CPU feature (SSE 4.1) but that is all. Because of the lack of details, we have taken the time here at Puget Systems to perform our own testing to determine what hardware runs Arnold the best. Based on this testing, we have come up with our own list of recommendations.
When it comes to CPUs there are two main specifications that define the capability of a CPU:
- The frequency directly affects how many operations a single CPU core can complete in a second (how fast it is).
- The number of cores is how many physical cores there are within a CPU (how many operations it can run simultaneously).
Whether a high frequency or high core count CPU is better depends on how well a program is designed to take advantage of multiple CPU cores (often referred to as multi-threading).
In the case of Arnold, as well as most other CPU-based rendering engines, scaling across multiple CPU cores is extremely good. Clock speed is helpful too, but sacrificing a little bit there to substantially increase the number of cores will be well worthwhile. Here is a chart from one of our Arnold CPU Comparisons showing still image render performance within Maya:
As you can see there, higher core counts directly improve performance. Clock speed is a factor as well, so you don't want to use a chip with extremely low per-core speeds, and there are differences between AMD and Intel processors - but those are generally the secondary considerations, after the number of cores.
Video Card (GPU)
The video card selection does not matter at all for Arnold, but if you use other software alongside it then base your selection off what those applications need. For example, if you use Autodesk products like Maya or 3ds Max - both of which include Arnold as their built-in renderer - then a NVIDIA Quadro would be a good choice.
While the exact amount of RAM you need is going to depend on your particular projects, for Arnold we generally recommend 32GB. That should be plenty for rendering even very complex scenes, but our systems do support more for those who need it. If you run other software alongside Arnold, keep that in mind when selecting how much memory you get.
Storage (Hard Drives)
With the falling costs associated with SSDs, we almost always recommend using an SSD for the primary drive that will host your OS and the installation of Arnold and other software. The high speed of SSDs allows your system to boot, launch applications, and load files many times faster than any traditional hard drive. If your budget allows, it is also a very good idea to have a second SSD that can be used to store your active projects to further decrease load and save times.
Since SSDs are still more expensive than traditional drives per GB, for long term storage we recommend using a traditional hard drive (or two if you need even more storage!). Using a SSD can be useful in some situations, but most of the time the high performance of an SSD is simply not required for a storage drive.