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OmniX · Aug 30, 2006, 10:47 PM

i'm looking into getting an external HDD and am wondering if there is any performance difference between the Firewire (400) and USB2 interfaces on a modern mac (i.e. Intel/Tiger). In other words, does FW still have an advantage over USB2, and is it thus worth shelling out some extra bucks for a dual-interface case? Or should I save my pesos and just get a cheap USB2-only case?

A related question: is there any appreciable performance difference between a (P)ATA and SATA 3.5" drive housed in an external case?

thanks in advance for any advice --
ox

ps: just out of curiosity, is there any word on if/when Macs might start using eSATA? aside from the fact that it doesn't carry power, for external drives eSATA seems to be far superior to USB or FireWire... is eSATA at all common in the PC world at all -- if so can we expect it on the Mac soon enough?

chefpastry · Aug 31, 2006, 02:24 AM

I could be wrong, but, as far as I know, Firewire is a faster bus than USB2. Doesn't matter if you're using a G3, G4, G5, or Intel. As for PATA vs. SATA, the bottleneck will still be the bus and it shouldn't matter if you use PATA or SATA in a Firewire or USB2 enclosure.

Lastly, keep in mind that not all chipsets are created equal...

Tuoder · Aug 31, 2006, 04:05 AM

FW400 has a maximum theoretical throughput of 400Mbps. USB 2.0 has a Maximum theoretical throughput of 480Mbps. In practice, however, Firewire 400 sseems to be faster. (P)ATA133 (1064Mbps) and SATA (1500Mbps) would both be bottlenecked running through either bus.

OmniX · Aug 31, 2006, 08:12 AM

Originally Posted by chefpastry

I could be wrong, but, as far as I know, Firewire is a faster bus than USB2. Doesn't matter if you're using a G3, G4, G5, or Intel. As for PATA vs. SATA, the bottleneck will still be the bus and it shouldn't matter if you use PATA or SATA in a Firewire or USB2 enclosure.

Lastly, keep in mind that not all chipsets are created equal...

chefpastry, could you elaborate on your chipset comment? are you alluding to the Oxford 911 FW controller-- is this still the thing to get? Are there different USB2 controllers out there, of differing qualitiets/performances?

ghporter · Aug 31, 2006, 10:43 AM

Aside from the maximum theoretical speeds of the two connection methods, keep in mind that Mac drivers for firewire tend to be better than Mac drivers for USB (while the opposite is true for Windows drivers-interesting little bias, eh?).

Further, USB 2.0's theoretical max is in a "burst" mode, not continuous data transfer, while firewire's max is constant.

Put the two together, and you usually come up with firewire being faster on Macs, especially with large files, while USB 2.0 usually works out faster on PCs, particularly with small files.

And there are some firewire chipsets that just do not do as well at managing the connection as others do...which is what I think chefpastry was talking about.

TFunkadelic · Aug 31, 2006, 12:28 PM

ghporter is correct. USB 2.0's rating is deceiving. Firewire 400 is actually the faster of the two, which is why you see it used in applications where it matters, like audio and video devices.

tomrock · Aug 31, 2006, 06:08 PM

Why don't you just spend a little more and get a case that supports both? You never know which you'll need.

mduell · Aug 31, 2006, 09:15 PM

Originally Posted by ghporter

Aside from the maximum theoretical speeds of the two connection methods, keep in mind that Mac drivers for firewire tend to be better than Mac drivers for USB (while the opposite is true for Windows drivers-interesting little bias, eh?).

Further, USB 2.0's theoretical max is in a "burst" mode, not continuous data transfer, while firewire's max is constant.

Is S400 Firewire really 392Mbps isochronous?

USB has no "burst" mode. There are control transfers, isochronous transfers, bulk transfers, and interrupt transfers.
IIRC the isochronous transfer speed is 192Mbps; bulk transfers should do a little better.

OmniX · Aug 31, 2006, 11:28 PM

Originally Posted by mduell

When Apple adds an eSATA port (with multiplexing support) and an HD screen (1920x1200), I'll buy a 15" MacBook Pro. It's going to be a while..

Mark Duell -- what's the situation with eSATA on the PC side of things. Is it common? Your signature is intriguing -- has there been any speculation/thoughts on when/if Apple might adopt it? (or would this kill/mortally wound FireWire?)