At 4:30 PM -0600 1/3/2012, Kris Tilford wrote:
That being said, USB 2.0 can be flakey sometimes, BUT, this is
almost always because a certain USB 2.0 chipset has problems with OS
X. We were talking about a real Mac, with Apple supplied USB 2.0, so
in this case, USB 2.0 should be solid, and fast.
If you're using a 3rd-party USB 2.0 card, especially one that
requires its own drivers, it could be slower, or screwed up in OS X,
but generally Apple supplied hardware works at full speed, and
should be nearly identical in speed to Firewire with a single 2.5"
external HD. If you had an external SSD that would be different, USB
2.0 would be slower than FW800.
OTOH, I just got a G-Drive (Hitachi) with FW800/USB2, and FW800 is really
faster than USB2 (on the same drive), at least twice the speed.
Even when connected to a FW400 port, it's still way faster than USB2.
FW400 & FW800 should be virtually identical with the same single HD.
You need at least 2 HDs in a RAID configuration, or an SSD to get
greater speed.
USB 2 is a raw 480 Mbps. That's an average throughput of around 35
MB/sec IF all conditions are perfect AND you have fast CPU to drive
it. heh. USB 2 drive + ffmepg OMG ROFLMAO its soooo bus speed
limited.
FW400 is a raw 400 Mbps. But FW has an overhead of under 10% and is
mostly controller & DMA driven. So it's average throughput is around
38 MB/sec, even on a slow CPU.
FW800 is ... you get the idea.
Now, case in point:
I have two identical external boxes here with identical Hitachi SATA
drives in them. They are high-end La Cie d2 Quadras (USB 1, USB 2,
FW400, FW800, eSATA).
If I plug one in via USB 2, I'm lucky to get 28 MB/sec. via FW400
I'm seeing around 33 MB/sec. And when I move over to a PB G4, that
has FW800, I'm seeing around 41 MB/sec with higher bursts.
Conclusions: SSDD. USB sux. FW400 is nice. FW800 is better.
Modern SATA drives need faster butt-interfaces because the HD is NO
LONGER the bottleneck it usta be.
sigh. Now when is Intel going to stop farking around with light peak
over copper and offer the full implementation over fiber???? 10 Gbps
per channel is sooo yesterday!
- Dan.
--
- Psychoceramic Emeritus; South Jersey, USA, Earth.
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