Recently, we have seen a wide variety of recorders being released that write video directly to Solid State Hard Drives (SSDs). These recorders include the Sound Devices PIX240, CineDeck, Atomos Samurai, the BlackMagic Hyperdeck Shuttle, and the Convergent Design Gemini 4:4:4. SSDs can be very fast and have become very price competitive compared to other memory cards. The high-speed Sandisk Extreme Pro Compact Flash cards that are required for ProRes recording cost around $7 per gigabyte, versus a comparable SSD that can be purchased for less than $2 per gigabyte. However, these drives were built to be used in computers, and it can be a bit confusing to choose the right drive for a video recorder.
In order to find a drive that works, you should first calculate the data rate requirements for the compression format you are recording. SSDs are usually rated in terms of maximum read speeds in megabytes per second (MB/s), however most compression is described in megabits per second (Mb/s). To converts bits to bytes, just divide by 8. For instance, ProRes HQ is a 220 Mb/s compression; divided by 8, it is 27.5 MB/s. Most drives, however, only list their maximum data rate for reading or writing; for video, we need a drive that can maintain a consistent data rate. That’s why determining the average sustained read/write speed is so important.
Fortunately, there are many great websites out there that do all sorts of testing on drives. One of my favorite sites for this is Anandtech – they have an SSD comparison tool that is a great reference. You can compare various drives and see their average read/write speeds during heavy use, as video is one of the heaviest uses of a drive. This average doesn’t guarantee the drives will hold a sustained date rate, but it is a pretty good indication. ProRes HQ has a relatively low data rate, but I found that if the average data rate (read/write) of the drive is well over 27.5 MB/s then it will work well. Uncompressed video, though, has a data rate that is quite a bit higher. Recorders such as the CineDeck, HyperDeck Shuttle, and Gemini 4:4:4 all record uncompressed, which can be up to 1.5 Gbps (187.5 MB/s) or higher in the case of the Gemini, which records in 4:4:4. Looking through all the different drives that are available, it may seem that there are many options, but each drive needs to be tested in the given device to make sure it can give consistent results.
Manufacturers will often list all the drives that they support; this is usually the best reference. The PIX240 suggests their own drives, which are the 256 GB Samsung 470 series (MZ-5PA256). CineDeck has a FAQ, which can be viewed here, suggests a super fast PhotoFast drive for uncompressed recording. Blackmagic Design has five recommended drives including the OCZ Vertex 3 drives, which we carry – you can view the full list here. Atomos suggests that you use only Intel SSDs, however we have found the same Samsung 470 drives used in the PIX240 work nicely. Finally, the Gemini 4:4:4 from Convergent Design will only work with their own proven drives, which are chosen to guarantee the best performance.