firewire or USB ext HD?

an external hard drive (SSD) is 40% more expensive when it connects via firewire 800 instead of USB. What kind of difference in system backup times are we looking at between the two?

You might find this interesting as a comparison of the differences between USB and Firewire. Their discussion of speed differences includes the following

FireWire 800 is substantially faster than Hi-Speed USB, both in theory and in practice.

USB 3.0 (released November 2008) gives a theoretical speed of 4.8 Gbit/s, which is about 5 times faster than FireWire 800, substantially faster than any of its competitors or predecessors until the next one is released.

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Macworld ran an earlier test where Firewire 800 was a pretty clear winner but it pre-dates usb 3.0.

jaguarMac said:

an external hard drive (SSD) is 40% more expensive when it connects via firewire 800 instead of USB. What kind of difference in system backup times are we looking at between the two?

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Hello - as mentioned by Sly...., the USB 3.x standard outperforms FireWire which is really a 'dead' technology w/ the Thunderbolt (TB) options and the new USB-C connection which seems to be a merging of USB w/ TB - so what USB ports do you have?

Another general question for Sly.... and others, despite these 'theoretical' speeds for these cable standards, a computer's ability to write to these external drives is a much slower process in my experience - e.g. I have a LaCie SSD to which I backup my MBPro's personal folders - both my laptop & the SSD are USB 3.0 - but if I have a few GBs to back-up (do this weekly), the process takes a good 20-30 seconds rather than a second or less - so, there are many other factors involved than just the potential speed of the connection - right? Thanks for comments - Dave

Thuderbolt is the fastest with an SSD installed, and USB3 second so you have to weigh up the cost of TB external caddies vs. USB3. If your Mac does not have TB or USB3, FW800 is still the go. Here are tests tables from Macpdate. The second table should interest you the most:-


How fast is USB 3.0 really? | Macworld

Does a 2008 Macbook Pro have a USB 3 port?

No, only USB 2.0 ports.

jaguarMac said:

Does a 2008 Macbook Pro have a USB 3 port?

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Hi again JaguarMac - you have an old computer likely running an old OS X - additional information would be useful - please tell us what you want to accomplish w/ using the 'fastest' ports available? Might just help to better advise w/ you current hardware - Dave

Now I see that the external drive I'm interested in also has USB 2 ports:
OWC 120GB SSD Mercury On-The-Go USB 3.0 / 2.0 SSD... in stock at OWC
I just want to do Time Machine backups maybe twice a month.

here's my older laptop:
late 2008, Macbook Pro 5,1 A1286 originally with OSX 10.7.5 Lion, Intel Core 2 Duo, 8GB RAM 1067MHz DDR3, 120GB SSD, upgraded to Yosemite 10.10.4, 2.4GHz Intel Core 2 Dual Boot, 15.4” screen

RadDave said:

Another general question for Sly.... and others, despite these 'theoretical' speeds for these cable standards, a computer's ability to write to these external drives is a much slower process in my experience - e.g. I have a LaCie SSD to which I backup my MBPro's personal folders - both my laptop & the SSD are USB 3.0 - but if I have a few GBs to back-up (do this weekly), the process takes a good 20-30 seconds rather than a second or less - so, there are many other factors involved than just the potential speed of the connection - right? Thanks for comments - Dave

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There aren't "many" other factors involved, usually just one -- the speed of the drives to read (in the case of the drive sending information to the backup drive) or write (in the case of the backup being written to) is the only other real possible "bottleneck" when you're talking about fast connection methods.

Your comment about how your "few GB" backup takes "20-30 seconds" rather than one second indicates to me that you're confused about the difference between gigaBITS (the speed connection methods are advertised, such as USB 3.0's theoretical top speed of 5Gb/second) and gigaBYTES. The latter is eight times larger than the former (8bits=1byte), so if you had let's say 5GB (note the capital B for bytes) to backup and connected it to a drive via USB 3.0, instead of taking one or two seconds, it should take eight to 16 seconds (there's some communication and "handshaking" that goes on with connected drives first, which adds a little bit of time but not much).

Then there's the factor of spinning HDs versus SSDs: for the latter, transfer speed will go as fast as USB 3.0 can handle (more on that in a second), whereas spinning drives have to "spin up" to top speed to do a transfer, which can add a bit more time.

Finally, USB 3.0 doesn't even reach 5.0Gb (small b for bits) per second in real world use. As has been typical of USB since forever, your actual speed is anything up to 40 percent less than the theoretical maximum. When you add these factors together, even between two SSD drives, a 5GB transfer between the two machines is going to take longer than eight seconds (but probably not a lot longer in that case). Throw in one more more traditional spinning drives into the mix, and 20-30 seconds sounds about right/a little on the quick side for such a transfer.

FW and FW 800 had an advantage over USB 1.1 and 2.0 in that it was faster AND it had less "overhead" which brought down the maximum speed in real-world use, so a FW800 connector, for example, could get very close to 800Mb per second under good conditions.

Anyway, hope that clears it up a bit. USB 3.0 is very fast and more than good enough for most consumer usage, Thunderbolt seems to have evolved to where FW was headed eventually (and can be used for FW stuff with an adapter) so its currently considered a "pro" level connector. As mentioned elsewhere, USB 3.1 and beyond (4?) and Thunderbolt 3 look like they are going to converge (TB can already "do" USB using an adapter) as far as connectors go, using the new USB-C connector as seen in the Retina MacBook. Eventually, that port will be both a USB-C and TB connector. Nice.

Thunderbolt 3 brings 40Gb/s to USB-C physical connector | MacNN