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Transfer Speed- USB2 vs. FW400 vs. FW800

I'm looking to get a 2nd external drive for my G5 2Gdual (2006). Like most people, I want the fastest I can get. But only within a budget. I'll be doing video work (Fianl Cut), Sound recording (using ProTools LE), and backups.

I've read that USB2 can have burst speeds of 480Mbps. While Firewire 400 has a sustained of 400 Mbps. I'm assuming that Firewire 800 can have sustained rates of 800 Mbps.

1) Are these rates for read and write? (for each)
2) When they say "burst", how much data are we talking about?
3) Can I expect these nominal rates with my G5?

G5 dual core 2Ghz, 2.5 GB, 160, 300GB & 300GBfw, Mac OS X (10.4.7), FCE HD, FCSP5.1

Posted on Sep 4, 2006 8:10 PM

Reply
10 replies

Sep 4, 2006 8:31 PM in response to Lawrence Borreson

Hi Lawrence;

I can't answer for Firewire 800 because I have never had any disk of that type to test. But I have tested both USB 2 and Firewire 400. I have found Firewire 400 to be between 20 and 40% quicker then USB. While the burst rate for USB is higher the overhead of the USB protocol is also higher so that overall throughput is lower.

Allan
User uploaded file

Sep 4, 2006 11:58 PM in response to Lawrence Borreson

The numbers are theoretical. USB2 at 480 Mbit/s should be faster than Firewire at 400 Mbit/s, but it's not - to the contrary. The performance one gets in practice depends a lot on the bridge chip, and in case of USB, also on the CPU architecture (USB2 drives are noticeably faster on Intel Macs - though still way slower than Firewire 400 let alone Firewire 800).

See a performance comparison in this test of the same drive using different interfaces. I've got an enclosure with USB2, FW400 and FW800 myself and can confirm these numbers.

The fastest is of course neither USB nor Firewire, but SATA (or its external variant: eSATA). It requires buying a PCIe SATA controller though, so it's more expensive - the disks will work at the same speed as they work on the internal controller. Or even a little faster (if it's SATA II at 3 Gbit/s). So that's the best option if you want top performance. See this thread for an example. (Note you would need a PCIe card, not PCI-X). Or check out barefeats or AMUG for tests of different cases, controller cards etc.

If you're on a budget, get a Firewire 800 drive with decent bridge chip (Oxford 92# comes to mind), that works excellent for backups etc.
I'm using the Firewire 800 (=IEEE 1394b) version of this case, and put a 400 GB ATA drive in it.


Quad G5 Mac OS X (10.4.7) 4 GB ECC RAM, Raptor 150 GB, Seagate 750 GB, GeForce 7800 GT

Sep 5, 2006 7:02 AM in response to boli

Those were some informative links. It looks like I may be checking into getting a FW800 (ieee 1394b) drive(s). I've found some links to PCIe boards on another thread. Until I start researching them further, they all look very similar.

If I can't find out if the chip set is the Oxford 92# on a drive box, how much difference might one see in a lesser chip set?

I've noticed that the drive housings I've seen pictured on several sites have (2) 1394b jacks on them (including the Maxtor One Touch II I currently have). Is this for daisy-chaining drives? If so how many and what would be the impact on transfer rates?

Sep 5, 2006 10:14 AM in response to Lawrence Borreson

Those were some informative links. It looks like I
may be checking into getting a FW800 (ieee 1394b)
drive(s). I've found some links to PCIe boards on
another thread. Until I start researching them
further, they all look very similar.


barefeats.com should serve you well in this regard.

If I can't find out if the chip set is the Oxford 92#
on a drive box, how much difference might one see in
a lesser chip set?


Dunno if there even is another bridge chip for Firewire 800. I've seen very bad performance with some non-Oxford 911 Firewire 400 bridges though. I dunno what the sarotech enclosure uses that I linked to, but it's certainly as fast as expected.
I think OWC do list the chip inside their enclosures (probably all Oxford 9##).

I've noticed that the drive housings I've seen
pictured on several sites have (2) 1394b jacks on
them (including the Maxtor One Touch II I currently
have). Is this for daisy-chaining drives?


Yup.

If so how
many and what would be the impact on transfer rates?


*Searching Apple's support pages for "Firewire FAQ*
Ah yeah, here we go: Firewire FAQ

Daisy chaining shouldn't have much of an impact when a single drive is transfering data at a time.

With multiple drives transfering data simultaneously I'd expect transfer rates to drop accordingly - as a single drive doesn't max out Firewire 800, I'd expect performance of two such drives in a daisychain to run faster than at half their normal speed, but slower than half of what FW800 can do (100 MB/s, dunno if there's some overhead).

Sep 5, 2006 11:09 AM in response to Lawrence Borreson

No problem. BTW, I just checked OWC's 3.5" enclosures. IMHO they're mostly inferiour to the sarotech one I linked to - only the MacAlly aluminum thing comes close, but it's got no integrated power supply, while the sarotech does (less clutter -> big plus in my book).

I used to have one of those clear plastic enclosures, just like most at OWC are. While performance was alright, heat dissipation wasn't (neither these nor sarotech use a fan, but heat dissipation of aluminum enclosure is much better of course - and cool drives live longer)

These dual-drive ones make a better impression, but I've got no personal experience with them. Dunno if their fan is loud.

For your viewing pleasure, here are my benchmarks using the sarotech enclosure with a Hitachi 400 GB drive:
FW800
FW400
USB2

Sep 5, 2006 11:30 AM in response to boli

I have one of OWC's FW800 dual-drive RAIDs. The fan on them is very quiet - the fans from my Quad make more noise, even at their lowest speed.

OWC also sells single-drive aluminum enclosures. There's no fan in them, but the aluminum case should dissipate heat reasonable well. Certainly better than their plastic enclosures when it comes to heat.

Sep 8, 2006 9:13 AM in response to Lawrence Borreson

I bought it with the two drives installed (2 x 250GB). I believe they are Hitachi drives, but I can't tell for sure; as the case uses a hardware RAID, the individual drives don't show up in Disk Utility or anything else.

Anyway, it's a RAID 0 in hardware. I use it as a video media drive, so the speed is more important than redundancy. It's capable of transfer rates in the 70+MB/sec range.

Transfer Speed- USB2 vs. FW400 vs. FW800

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