Guys, I came across something rather enlightening, and troubling for those of use that use external HD enclosures. In a particular PC build for a customer, the HD's are very close the IDE connectors on the mobo. Sometimes it's like this, other times the IDE connectors at way at the top of the mobo. Since I'm very particular about the aesthetics of PC's we build, and air flow, I wanted to use 6" IDE cables for a cleaner look, and less obstructive to air flow (yes I also sleeve my cables as well). I happened to have one, that happened to come with a pack of FireWire (FW) cables. It was an 80-pin cable, which is supposed to be for ATA/UDMA66+ HD's.
Come to find out, even though they are indeed 80-pin IDE cables which are supposed to be UDMA/ATA66+, they are not. I hooked up a HD with one and the BIOS kept complaining it was an ATA100 or higher HD, but the cable was only "40-pin" and of course would only run at UDMA 33. Apparently, (as the included FW cables indicate), even though they are 80-pin, these IDE cables are **ONLY** for USB or FW external enclosures. I thought they were simply just a shortened ATA66+ cable, apparently not. Now this brings up an interesting area of the data transfer speeds. UDMA/ATA33 is 33MB/sec max theoretical transfer speed, USB 2.0 is 60MB/480mb/sec, and FW400 is 50MB/400mb/sec. Both of course more than 33MB/sec. So any external enclosures using these shortened pseudo 80-pin cables are not getting the maximum transfer of which they are capable.....right? I doubt anyone has ever removed the 4-6" 80-pin IDE cable in an enclosure and tried a typical ~18" 80-pin IDE cable. It would be interesting to do some benchmarks before and after. I may when I have the time. Perhaps there is "something" in the USB or FW interface that does not require real 80-pin cables.?? Even so, you're still only dealing with a cable that can only transfer 33MB/sec so it seems we're getting short-changed here with the drives in these enclosures not performing as well as they could. However, it could be due to the fact the mobo is where the "80-pin cable detector" so to speak, is located. This is why an 80-pin cable has a different color, usually blue, that connects to the mobo, and the gray or black connects to the drives (master or slave depending on jumper position). If you reverse the cable, the BIOS will think it's an old 40-pin UDMA 33 cable. Maybe these shortened cables ARE the same cables, just missing this 80-pin cable detector connector pin since they are not required because they are in an external enclosure. But, it seems like it would be cheaper to just make shortened 18" cables, instead of a special 6" cable void of the 80-pin cable detector pin. Any info or thoughts welcomed. (BTW in case anyone is wondering about USB 2.0 Vs FW400, FW is actually a little bit FASTER sustained speeds in actual use since USB 2.0 has more "overhead". Small files, it's not going to matter. But huge files like digital video, or copying/backing up your entire main HD, FW will be a bit faster. FW800 is out now which as the name implies is supposed to be twice as fast as the old FW, and there's probably a new USB protocol out now that's faster than 2.0. If not, there no doubt soon will be). -Clint God Bless Clint Hamilton, Owner http://OrpheusComputing.com http://ComputersCustomBuilt.com ============= PCWorks Mailing List ================= Don't see your post? Check our posting guidelines & make sure you've followed proper posting procedures, http://pcworkers.com/rules.htm Contact list owner <[EMAIL PROTECTED]> Unsubscribing and other changes: http://pcworkers.com =====================================================
