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External USB Hard Drive Uncached Speed is Slow- How can I improve this?

Posted on 2004-10-02
Medium Priority
Last Modified: 2012-06-27
I went to www.pc pitstop and ran a test that tested my whole system. Everything was fine except my uncached setting on my external 40gb USB hard drive (ez bus made by apricorn) . the USB runs very well except for one thing- it is slow. it was diagnosed that is had "unusually slow performance"; it's uncached speed is 8mb/s. how can i improve the speed?

I have a toshiba satellite A45, p4 2.8 gb cpu, home xp, 1 gb ram.

pcpitstop made some recommendations how to do it but i could not follow the instructions-

1) terms like DMA confused me. they said: "Make sure DMA is enabled on all disk drives. Not using DMA mode can cause a significant reduction in disk speed".

2) they also suggested- Update the driver for your disk controller. but if i have an external does this still apply

3) and finally, "If you have a system based on the Intel chipset, you can often increase performance by using the Intel Application Accelerator."

i am in over my head.
Question by:cityman12000
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LVL 17

Expert Comment

ID: 12208449
I assume you have a USB 2.0 hard drive, and are plugging into a USB 2.0 port via a USB 2.0 cable.  Any non USB2 stuff could drop you to USB 1.1, which would be quite slow.


Author Comment

ID: 12208509
yes, it is a usb 2.0 external hard drive and it is plug in to a usb 2.0 port and with a us usb 2.0 cable. everything is new-recent 4 months old so the technology is 'new'.

Author Comment

ID: 12209824
to the reader; the question of the usb still in in effect.  the administrator comment was referring to a different situation.

so again the question is: External USB Hard Drive Uncached Speed is Slow- How can I improve this?
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LVL 17

Expert Comment

ID: 12214286
First, running uncached will affect the performance -- the system simply can't optimize throughput to the device.  Then throw benchmark-style operations over USB, with flushing, and yeah, I could see it running slow.

Second, the drive is only a 4200RPM, with a seek of 12ms, so it will certainly report as a slower-than-average drive (most average drives these days are 7200RPM, 9ms).  Add in USB in the way, and not caching, and you'll see slower performance.

Also, please clarify that you mean 8 Mb (mega-bit), not 8MB (mega-byte), in the performance test.  If it's 8MB, that isn't off by much, and I could see that coming up in a test.  8Mb would indeed sound off.

Have you done all the windows updates, gotten updated bios & motherboard drivers, etc.?  I don't think it should make the difference here.  Also, have you simply tried on a different machine, just as a sanity check?


Author Comment

ID: 12214440
according to pcpitstop- (cut and pasted this reply)  8 MB/s  (so it would be 8 mega-byte)

yes i have all the win updates (except for sp2).

i am not sure about a drive controller update- does it apply to external drives?

and what about pcpitstop other recommendations- dma being enabled and intel application acclerator?

i have another external disk drive, made by the same company and same model. i will check that and get the results back to you.

Author Comment

ID: 12220087
according to pcpitstop the final grades of the uncached speed was:

drive c:  (internal)14 MB/s, 81%
drive e: (external) 12 MB/s, 69%
drive f:  (external) 20 MB/s. 115%

they wrote: uncached speed is measured in megabytes per second (MB/s). When a percentage is shown for uncached speed, it compares the performance of the drive with those of systems in our database with the same processor and clock speed. (Our database currently has 2046 similar systems.) A rating of 200% means a disk is twice the performance of similar systems, 50% means it's half the performance. Uncached speed is most affected by the physical hard disk and the disk interface.

there was no alerts this time to the problem, which is good. But you can see the Drive E is the slowest drive whereas the other external is almost twice as fast. Drive E was the original problem drive! (even though i wrote- drive f above- i moved the external drives to a different usb port).

before i tested, i did chkdsk and defrag. the only other difference would be that the slower drive had 38% free space; whereas the faster drive had 58% free space. Since uncached speed (according to pcpitstop) is most affected by the physical hard disk and the disk interface.. i doubt -free space-  is the problem.

Can you think of something?

also.. i wonder if i should call the company and get a replacement. i bought it Aug 13, 2004. what is your opinion?
LVL 17

Assisted Solution

davebytes earned 1000 total points
ID: 12220846
Well, given that the new number is now 12MB/s, I'd say you are getting pretty decent performance numbers.  Heck, your internal drive isn't that much faster, and this is only a 4500 RPM drive.  I'm assuming drive F is also a USB2 drive, but maybe a 3.5" 7200RPM unit?

I really don't see anything problematic with those numbers.  And if everything is that recent, and you are up to date on motherboard drivers (usb controller, etc.), I can't see you doing much that would affect the numbers you are seeing.  The fact that drive F comes in > 100% means that you can't really rely on the % numbers, or their 'commentary', to necessarily define whether things are/aren't working well on your system.

FYI, I did some searching, and one review of a similar Apricorn model was tested as 12-15MB/s in performance.  So again, I don't necessarily think you actually HAVE 'performance problems'.  ;)


Author Comment

ID: 12221979
you will not believe it but i emailed apricorn's tech support. they agreed to a swap.

maybe i do not have performance problems but the difference between the two (exact same models with rpm's) of 69 and 115 is considerable. and since apricorn agrees to a swap... maybe they know something you and i don't.

but your research is impeccable.

so now,should i swap?
LVL 17

Accepted Solution

davebytes earned 1000 total points
ID: 12223424
Wow.  Well:
- if they offered to swap you a new one, and
- the two drives (E and F) are identical USB drives, and you tried swapping cables, and USB jacks, etc., then

go for it! ;)

If two identical drives don't behave identically, and you rule out a bad cable, bad port, whatever, then yeah, I'd certainly take them up on a swap.  Maybe there's a glitch in the drive hardware or drive controller.


Author Comment

ID: 12223827
that is just it- they do not behave identically. i switched USB ports, chkdsk and defrag - but not cables (maybe i should try that- but ... enough is enough).
also in an earlier letter to acronis- they suggested the following:
Make sure that the drive is set for quick removal.
Check out Microsoft Knowledgebase Article # 828012.;en-us;828012&Product=winxp

i did this and the results were the same.
So, i guess you are right. I will call email them tomorrow and let you know what happens.

Author Comment

ID: 12243385
i received a phone call from apricorn tech support. they already sent a replacement unit. now that is great service and an excellent company.

i have to recommend them as a solid company!!

davebytes-- thanks for your help, much appreciated!!!

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