Theoretical hard drive speeds are one thing, real world benchmarks are another. In the interest of tedious science, here are a few numbers.
Black Magic Disk Speed Test is a useful free app for determining hard drive speeds with regards video production. After my recent MacPro5,1 upgrades here’s a few comparative speed tests with HDD, SSD on SATA, SSD on PCIe and RAID SSD on PCIe.
SATA II with a knackered HDD
First off, just for laughs, an old Western Digital Blue 7200RPM spinning drive on the MacPro SATA bus, 3TB capacity, used and abused, fragmented to hell with only 3GB of free disk space remaining. 90MB/s write and 80MB/s read.
SATA II with a new HDD
Next up – and probably more typical performance from a spinning HDD on the SATA bus – a 25% full Toshiba 7200RPM 6TB drive with less than 6 months on the clock. 173MB/s write and 200MB/s read. Just creeping into 4K video editing territory but in practise this would choke doing any sort of multi-layer 2K compositing.
SATA II and a single SSD
Below, Samsung 850 Pro 1TB SSD – also on the MacPro SATA bus – I tested this SSD on a PCIe card and it ran full speed 550MB/s both ways but via SATA it’s bottlenecking at 251MB/a write and 265MB/s read. This is (currently) my OSX Yosemite boot drive and I didn’t notice much of an operational boost when comparing 265MB/s SATA vs 550MB/s PCIe to be honest; but the rest of my system is not exactly fast, system RAM is slow (48GB DDR3 at 1066MHz) plus this CPU would be considered average performance by 2017 Mac standards (2010 2.4GHz 8-core).
SATA II with double HDD RAID
Taking things one step further – running two 6TB 7200RPM HDD as striped RAID on the internal MacPro5,1 SATA2 bus. Read 350MB/s and write 401MB/s, these figures are interesting because you can overtake single SSD drive speeds on the SATA2 bus and for considerably less money. A 1TB SSD is around $500 and maxes out around 270MB/s on the SATA2 bus, whereas 12TB spinning in RAID on two SATA2 ports costs a mere $200. No doubt running three drives in a SATA2 RAID setup would be a very cheap way of working with 4K footage (at the risk of a single drive failure, so make sure you have plenty of USB3 single disk back-ups if you want to sleep at night!).
PCIe with double SSD RAID
And finally – here’s where things get a bit more interesting – striped RAID with two 480GB Mercury Electra 6G SSDs, both on their own PCIe card. I’m surprised at the low-ish write speed when you consider the theoretical bandwidth but otherwise happy with 604MB/s write and 943MB/s read. This RAID has 256k block sizes (I’m no expert but this seemed correct for large data chunk video files). Perhaps smaller block sizes will be faster?
Will follow up with some real-world feedback using Fusion, Resolve and Nuke (6.3v8) in the coming weeks.
Best bang-for-buck is use the internal MacPro5,1 SATA2 bus and stripe two (or more) spinning HDDs into a RAID.
Best performance ignoring cost is multiple SSD as RAID on the PCIe bus … but then we already guessed that would be the case.