PostMicroTools
Reference + calculator
Disk throughput
How much sustained read/write speed your drive needs to play your footage — and which media keep up. Required throughput = codec data rate × simultaneous streams.
Typical sustained throughput
| Media | ~MB/s sustained | Good for |
|---|---|---|
| SD UHS-II | 250 | HD/4K long-GOP capture |
| HDD 7200 (single) | 200–250 | Offline proxies, archive |
| SATA SSD | ~530 | 4K ProRes, light multicam |
| Thunderbolt 3 SSD | ~2500 | 4K/6K ProRes multicam |
| NVMe Gen3 / Gen4 | 3000 / 6500 | RAW, 8K, heavy multicam |
| RAID HDD (8-bay) | ~1000 | Shared finishing, RAW |
Sustained vs burst
Marketing numbers are usually burst (cache) speeds. Editing needs sustained throughput — the speed a drive holds while reading/writing continuously. It's often well below the headline figure, especially on HDDs as they fill.
Will the drive keep up with the timeline?
Stutter during playback is more often a disk problem than a CPU problem. One stream of UHD ProRes 422 HQ needs about 88 MB/s sustained; a 4-camera multicam of the same format asks for ~350 MB/s continuously — comfortably inside an NVMe SSD's envelope, marginal for a SATA SSD once other I/O piles on, and hopeless for a single spinning disk that delivers 150–250 MB/s at best and much less once fragmented.
The direction matters too. Editing reads several streams while writing renders; a shared NAS over 10 GbE tops out around 1 GB/s theoretical and meaningfully less in practice, split among every editor on the system. This reference maps common codec/resolution/stream-count combinations against realistic sustained throughput for HDDs, SATA/NVMe SSDs, RAID configurations and network links, so you can diagnose — or predict — the bottleneck before the session.
It's also the sanity check for on-set recording: a camera writing X-OCN ST or 8K REDCODE needs media rated for sustained writes, not the burst figures printed on the label.
Why does my drive benchmark fast but still drop frames?
Benchmarks report burst or short-window speeds; playback needs sustained throughput while the OS, cache spill and other apps compete for the same disk. Fragmentation and a nearly-full SSD (throttled SLC cache) both cut real-world rates well below the benchmark.
Is RAID 0 a good idea for editing media?
It doubles throughput and doubles the blast radius — one dead disk loses the whole volume. It's acceptable only for reconstructible working media with the originals safe elsewhere; RAID 5/6 or a mirrored pair trades some speed for survivability.
What do V60 and V90 mean on SD cards?
Guaranteed minimum sustained write speeds: 60 MB/s and 90 MB/s. A camera recording 400 Mbps (50 MB/s) needs V60 minimum; high-bitrate RAW formats push into V90 or CFexpress territory. Burst ratings on the label don't protect a continuous recording.