Caretaker Download

Guide

What SSD speed do you need for 4K and 8K video editing?

One stream of 4K ProRes 422 HQ at 30 fps is 884 Mb/s, about 110 MB/s, by Apple's figures. The drive has to keep up with every stream you play at once, with room to spare.

Megabits vs megabytes

Codecs are rated in megabits per second (Mb/s). Drives are rated in megabytes per second (MB/s). Divide Mb/s by 8 to get MB/s.

4K and 8K ProRes data rates

Target data rates from Apple's ProRes white paper (April 2022):

  • 3840 x 2160, 24p: ProRes 422 471 Mb/s, ProRes 422 HQ 707 Mb/s.
  • 3840 x 2160, 30p: ProRes 422 589 Mb/s, ProRes 422 HQ 884 Mb/s.
  • 3840 x 2160, 60p: ProRes 422 1,178 Mb/s, ProRes 422 HQ 1,768 Mb/s.
  • 8192 x 4320, 24p: ProRes 422 2,011 Mb/s, ProRes 422 HQ 3,017 Mb/s.
  • 8192 x 4320, 30p: ProRes 422 2,514 Mb/s, ProRes 422 HQ 3,771 Mb/s.

So one stream of 8K ProRes 422 HQ at 30p needs about 470 MB/s. ProRes is variable bit rate, so busy, detailed shots run above these targets and simple ones below.

Data rates of one stream of 4K and 8K ProRes 422 and 422 HQ, in megabytes per second.

ProRes RAW, H.264 and HEVC

  • ProRes RAW: Apple says its data rates generally fall between ProRes 422 and ProRes 422 HQ. ProRes RAW HQ falls between 422 HQ and ProRes 4444. Unlike other ProRes, it keeps quality constant, so noisy or detailed images make bigger files.
  • H.264 and HEVC from cameras and phones have much lower data rates, so almost any SSD keeps up. Apple's white paper notes they are much harder to decode, so with these the processor, not the drive, usually limits playback.

Multiple streams and headroom

Add up every stream that plays at the same moment. A four-angle multicam of 4K ProRes 422 HQ at 30p is 4 x 884 = 3,536 Mb/s, about 442 MB/s. Picture-in-picture, split screens and cross-dissolves count too.

Then leave headroom. The speed test is a best case: the drive also writes renders and caches, and a nearly full drive is slower. A single SATA SSD tops out near its interface limit, so for 8K or multicam pick an NVMe drive on Thunderbolt.

The faster way: Caretaker

Caretaker's free drive speed test shows a drive's read and write speed as the formats it keeps up with, from H.264 to ProRes 422 HQ 8K, photos and music, so you can tell before a project starts.

Caretaker's drive speed test: read and write speed, and what the drive is fast enough for.
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Questions

Is 1,000 MB/s enough for 8K editing?

For a single stream of 8K ProRes 422 HQ at 30p, which Apple rates at about 470 MB/s, yes. For multicam or 60p, it isn't.

Do I need a fast SSD for 4K H.264?

Rarely for the drive's sake. H.264 data rates are low. Playback is usually limited by decoding, which is why editors transcode to ProRes or use proxies.