build it yourself external HD question

[wdfa89]

I put a WD 250GB, 7200, 8 mb cache HD in a Coolmax CD-309 external enclosure. It is supposed to be operating USB 2.0 but it seems way too slow for that, especially compared to my WD 120GB external HD.

Yes, it is plugged into a USB 2.0 port. I have tried switching ports, cables. All comparisons with my other external have the new one taking twice as long to tansfer files to and from.

Any ideas, thoughts on things to check would be welcome

[Greg12]

Sorry to tell u this but external devices will always be slower than internal devices.

[wdfa89]

I know that. I figured my two external devices would transfer at about the same rate. But I am thinking that ain't so. For grins I plugged my old external into a 1.0 port and saw what really slow actually is. I guess this new HD is going to be about half as fast as my old one.

[cjb1118]

Maybe try Firewire??!!? 8)

[Jayhawk]

Something is wrong somewhere.

USB 1.1 transfers at 1.5 mbytes per second, USB 2.0 transfers at 60 mbytes per second (40 times faster). According to usb.org a gigabyte of data should transfer in 34 seconds. That transfer rate is at the root hub level I believe (port level) so the port itself can only support 60mb for all devices attached. I'm assuming your two hard drives are plugged into different ports. There should be no significant difference between your two external drives. Things to consider:

If your not using XP you may not have the right USB drivers.

USB 1.1 cables can be used with USB 2.0 if they are 100% USB 1.1 certified (of course USB 2.0 cables need the same certification). A recent study of cable by USB.Org found that only 3 of 11 cables passed.

I would disconnect the drives and test each one seperately. I would test the transfer rate of each external drive using the same cable and same port to see if it's in the 30 - 40 second range for a gigabyte file for both drives. There may be something wrong with your new enclosure.

[sitlet]

usb 2.0 drives have been known to not work properly. do a search on here and you will find plenty of info. i personaly bought a usb 2.0 enclosure for my dvd burner and my hard drive, and had tons of problems. files wouldnt transfer all the way, dvds wouldnt burn, etc. so i got a firewire enclosure and have had no problems since. i would recommend getting a firewire enclosure

[rallynavvie]

Yeah, there was a poll in this forum a while back for USB2.0 vs FireWire and the latter won by a landslide. The problem I've seen with USB enclosures is the ATA to USB chipset isn't always the greatest. Most FireWire enclosures use the Oxford chipset which has always performed well which has greatly helped FireWire in the external drive market. I have 5 external FireWire devices and have had no problems with any of them. One has USB2.0 on it as well and I have noticed that it is a lot slower than the FireWire interface when I used it to transfer files to a friend's computer who didn't have 1394.

[wdfa89]

thanks for all the input/suggestions. Will probably give firewire a try on the next mod and/or computer.

I did find my problem: when I formatted the new disk I checked the box for "compress drive to save disk space" I do know how critical it is to do that on a 250gb drive. anyway I think that is what was slowing things up because once I unckecked it I was transferring just as fast as my other external HD (which, of course, did not have the box checked).

[Jayhawk]

It's always great when a problem gets solved. I never thought of that but it makes sense. Learn something new everyday.