quoted Drive figures are usually completely out of whack with reality.
if you see an (Mbps) then divide it by 8 for the Megs.
if you see a Drive with an (MBps) in the hundreds, don't believe it.
instead, divide it by 8.
no drive delivers anywhere near 3Gbps.
external drive very often don't perform as fast as internals for various reasons.
take a look at. Test Bench: Medea Firefly 2/240 FireWire Hard Drives
This was a while ago (2004) but the Firewire 400 and 800 protocol has been around since then.
though they are changing the chipsets and the way the computers buss integrates with these.
Also physical drive technology hasn't progressed massively since then either.
The performance of these drives depends on how they are configured, individually, in a RAID 0 or in a RAID 1. As individual drives, we saw sustained data rates of over 210 Mbps across the entire drive. This exceeds the capture/print-to-tape needs of 25 Mbps for DV by almost a magnitude. A RAID 0 (striped array) should show some performance improvement in some applications, and transferring huge files (such a video) might be one of them. We say "might" since this improvement will only be apparent if there isn't a bottleneck in the data flow somewhere else. In the case of the FireFly, that bottleneck is going to be the FireWire interface, which is limited to 400 Mbps. In our tests, we hit average sustained data transfer rates of around 230 Mbps, which is only a 20 Mbps increase over a non-striped (individual) disk. As a comparison, a quick test of another computer in our office averaged 425 Mbps on an equivalent internal hard disk and an internal striped array sustained 650 Mbps.
230 Mbps divided by 8 = 28.75 Megs per second
650 Mbps divided by 8 = 81.25 Megs per second
a high speed SATA internal drive in a laptop will outperform most external arrays unless these are top quality components which are striped.
external data bridges generally aren't up to the class of the internal bridge throughput on computers.. they are always upping the internal bus speeds on new computers. but what a physical drive can physically read from the head is always way way lower than that anyhow. Manufacturers stopped disclosing their sustained read and write speeds years ago. now they just quote the bus speed or the protocol and people think it's what the drive can read and write. not the case.
Good SSD drives look to be able to keep pace with ULTRA SCSI seagate velociraptors and that IS quick!
so, a small internal and fast SSD can fulfill specific needs, admirably. then having a simple backup and storage drive for the projects and one for sample libraries can prove very effective. if you have massive sample libraries though, then internal SSD's start to get out of whack in price performance terms.
Glyph are well respected Audio drive system manufacturers though. but just keep in mind what the physical drive itself is capable of in transfer and sustained read and write speeds.
you can Google.
bench tested drive transfer rates