I have a new blog on Post Magazine called: “Don’t Waste Your Money on Faster Storage.” You can read it here:
I get a lot of questions about what’s the “fastest” storage – and I wanted to explain that “fast” is a relative term.
As always, I’m interested in your comments.
P.S. By the way, there’s a math error in my Post article. USB 3 has a maximum data transfer rate of around 600 MB/sec
7 Responses to Post Blog: Data Transfer Rates
So it make’s no sense to buy a HD like this one if you are going to use FW800?
FireWire limits the maximum speed any drive, or collection of drives, can transfer data to or from your computer to around 85 MB/second. If you don’t need that level of speeed, then FireWire 800 will be fast enough. This is generally true for single-camera editing. Where the speed is insufficient in for many types of multicam editing.
saw your post on Post is oversimplified to the point of misinformation.
“- RAIDs are always faster than single drives”
Mirror are not faster. To the extent they have greater overhead then a single disk, they are slower. All other things being equal.
“- RAID speeds are, generally, the sum of the speeds of the drives they contain”
Not true for non-RAID 0 implementations. & contradicts your more accurate statement, “the maximum speed of a RAID is the SLOWER of the sum of the speed of all the hard drives it contains, or the protocol that connects the RAID.”
Sustained data throughput is ultimately limited by spindle speed. You correctly point out it may be further limited by protocol.
Spindle speed is over-rated. Protocols exert a MUCH greater impact on total throughput. The sustained throughput of a 10,000 RPM drive is no faster than a 5,400 RPM drive, when both are connected via FireWire.
You are correct in that a mirrored drive (RAID 1) is no faster than its slowest drive. However, very, very, very few video editors use a mirrored drive for editing – though many use them for original data capture on set.
Thanks for your quick response.
I understand that.
The drive on the link is a Dual Hard Drive unit with FW800. I guess the overall speed is the same than the Single Hard Drive one then.
In today’s technology, a single hard drive delivers about 120 MB/second of data. So, two should deliver around 240 MB/sec. (These are only rough approximations for speed.)
Since FireWire 800 tops out around 90 MB/second, the performance of a two-drive RAID is roughly the same as a single disk.
Thank you, Larry!