How to choose a processor for video editing

If you are serious about video editing, the performance of your computer matters a great deal. The higher the resolution you work with and the more work you put into processing your videos, the more you notice how long your PC takes to prepare each clip. Source file types, the codec and video resolution will all impact upon the speed at which you can edit, playback, render and export your finished work. Clips taken from your camera will likely be in a compressed format and will need to be decompressed to full-colour depth raw format before processing can take place. All of these tasks place a heavy load on both your CPU and GPU. So choosing the processor for video editing is actually about choosing the balance between the GPU and CPU.  Performance tends to be limited by the lowest denominator of the two.

There are many applications on the market for video editing but the way in which they work and the hardware requirements are remarkably similar. Right from Adobe Elements, Vegas Pro, Adobe Premiere Pro right through to Davinci Resolve, all these packages scale up with higher performance multi-core processors. Our testing has been undertaken using Adobe Premiere Pro as this is the most popular editing package in the enthusiast / professional sector.

Processor clock speed is very important for performance, we found Premiere Pro performance to scale directly with increased clock speed.  Processor core count is also important with strong benefits to using processors with medium to high core counts with performance not tailing off until core count reaches 10 or more after which the tail off is gradual.  The graph below shows how much more efficiently Premier Pro utilises high core count processors compared with photo editing performance in Adobe Photoshop when all processor cores are clocked at the same speed.

There’s a trade-off between core count and clock frequency as you move up the processor stack.   Both Intel and AMD processors with high core counts will operate at reduced clock speeds which will negatively impact overall performance.  For this reason, we don’t recommend utilising processors above the Core i9-7940X for general content up to 4k resolution.

Whilst many will assess the performance of a video editing systems’ CPU by disabling GPU (Graphical Processing Unit or simply your graphics card!) acceleration, this gives an inaccurate result.  When GPU acceleration is disabled, all the workload is handled by the CPU and multi-core processors show huge improvements in performance.  When GPU acceleration is enabled, the computer will, where possible, place complex multi-threaded calculations on the GPU in addition to the CPU.  In this scenario, it is important to achieve the correct balance between CPU, GPU and memory performance to avoid bottlenecks.

GPU acceleration is far more efficient so jobs can be completed in far faster time-frames than relying on a high core count CPU alone.  It is therefore often most beneficial to invest in very high-performance GPU, often multiple graphics cards can be installed in a single PC giving large performance increments with each additional card.  Where the option exists to utilise GPU acceleration, it is always wise to do so.  A growing number of codecs now enable GPU acceleration but where this isn’t available a very high core count processor will get chance to stretch its legs.  Even when GPU acceleration is available, Premiere Pro can still place significant loading on the CPU.

Another consideration should be the number of PCIe lanes and maximum memory supported by the processor.  The lower end processors only support 16 PCIe lanes and a maximum of 64GB of memory.  This is fine for low and mid-range systems which only utilise one GPU but higher performance systems requiring multiple GPU and a number of PCIe storage devices will become limited by the number of PCIe lanes.  The 64GB maximum memory will limit those working with higher resolutions.  Also worth noting is the fact that the higher end processors address memory in quad channel but the lower end models only utilise dual channel.  This can have a small but noticeable impact on performance.

The best value processor by far is the Core i7-8700K.  It has 6 cores and 12 threads and its high turbo clock speed of 4.7GHz offers good performance for video editing.  When coupled with a high performance video card, fast storage and lots of memory, this processor can help make an excellent video editing system.  We recommend using the i7-8700K when utilising a single GPU.  Those wishing to push the processor further can overclock but we recommend only mild overclocks.  An overclock to 5GHz can offer noticeable performance increases whilst maintaining stability.

For higher performance systems which utilise multiple GPU, we recommend moving up to the Core i9-7900X or the Core i9-7940X processors.  Both models utilise the higher performance x299 motherboard platform which provides a far higher number of PCIe lanes and are able to support 128GB of DDR4 memory in quad channel with the Gigabyte models also supporting 256GB and 512GB of registered DIMM memory for truly impressive high end systems.  The X299 platform is simply better at achieving a higher data throughput.

The key to achieving the best price / performance systems at each level is balance.  There is no point pairing a super high end processor with a single GPU, the processor won’t be fully utilised and the GPU will be running at 100%.  Likewise, a high end multi GPU setup running on a Z370 platform will max out the CPU and you won’t get the best performance from the GPU.  Your system is only as fast as the slowest component here.  Get the balance right and you get the best bang for buck.

You will find the RTX2080 GPU is an excellent partner for the latest 8 core CPUs on the Z370 platform.  If you choose an X299 platform system with 10 core or higher CPU, nothing less than the RTX 2080 Ti will suffice and buyers of the i9-7940X should consider using two RTX 2080 GPUs.