External USB 3.0 SSD, Fast sequential, excruciatingly slow random

Davste

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Jul 8, 2011
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Hi,

I have bought an "Integral 256 GB" external USB 3.0 drive. The sequential access speeds are really fast, but when it comes to small files (and 4K writes) it is EXTREMELY slow. Any ideas what might be the problem?

k3kec2.png


I've tried this on my (USB 3.0) laptop and on my PC with the same result.
Any ideas what might be the problem?

Thanks
 

razel

Platinum Member
May 14, 2002
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I get that issue with AS-SSD only with cheap flash drives. Which usually means that that internal SSD has a cheap SSD controller or more likely it is a USB flash drive in disguise.

Try running Crystal Mark instead and use a smaller 100MB file size. Last that I checked years ago AS SSD used 1GB test files.
 
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Davste

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Jul 8, 2011
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The problem is: The reason I bought this is to keep my workstation with a virtual machine on it. The performance has been REALLY, REALLY slow so far, though large files copy very quickly. I also notice that while the VM is open even doing basic stuff like navigating to folders takes ages. Moreover, it actually works much faster on the internal (slow) hard drive than from the external SSD. I have enabled write caching on windows. Is there anything else I can do apart from returning the damn thing?
 

Davste

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Jul 8, 2011
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This is..... painful to watch
2mg89c3.png

I will test it on 100MB and 4 runs now and see what happens, but it doesn't look promising.
 

razel

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May 14, 2002
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That Crystal Disk Mark 4k write bench is telling and that is done at 50MB. You have a USB flash drive. I wouldn't bother trying much else. To VPN to my job at work, instead of loading all of their crap VPN software onto my personal laptop, I run a VM off a USB flash drive as well. It has almost double the read 4k speed as your bench, but unlike your experience it is plenty fast for what I need.

Luckily Oracle's VirtualBox does a very good job of caching 4k writes. Benching Cyrstal Disk Mark within my VM to measure the USB drive's speed is far better than within my OS direct to the USB drive.

Try within your VM program to adjust it's write caching. Oracle's VirtualBox has some, but it is not in it's GUI. They are command line switches. Otherwise, there isn't much else you can do. Just look at what you bought as a fast sequential performing flash drive. I get a feeling we'll be seeing alot of these.
 
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Davste

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Jul 8, 2011
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That Crystal Disk Mark 4k write bench is telling and that is done at 50MB. You have a USB flash drive. I wouldn't bother trying much else. To VPN to my job at work, instead of loading all of their crap VPN software onto my personal laptop, I run a VM off a USB flash drive as well. It almost double the read 4k speed as your bench, but like your experience it is plenty fast for what I need.

Luckily Oracle's VirtualBox does a very good job of caching 4k writes. Benching Cyrstal Disk Mark within my VM to measure the USB drive's speed is far better than within my OS direct to the USB drive.

Regardless, there isn't much else you can do. Just look at what you bought as a fast sequential performing flash drive. I get a feeling we'll be seeing alot of these.

Screw that. 180 euros for this? I'm just going to return it, buy a normal SSD and an enclosure for it.
 

Cerb

Elite Member
Aug 26, 2000
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The problem is: The reason I bought this is to keep my workstation with a virtual machine on it. The performance has been REALLY, REALLY slow so far, though large files copy very quickly. I also notice that while the VM is open even doing basic stuff like navigating to folders takes ages. Moreover, it actually works much faster on the internal (slow) hard drive than from the external SSD. I have enabled write caching on windows. Is there anything else I can do apart from returning the damn thing?
Doubtful. Even Phison drives are faster than HDDs. The cost of an external SSD, or making your own external 2.5" USB 3.0 SSD, shouldn't be too much more than whatever this cost you.

That reads like it's basically a 256GB USB flash drive, or they also cheaped out on RAM, so it can't hold enough of the mapping tables w/o going out to the drive. The USB controllers generally have a minimal amount of RAM integrated, to hold just enough data to write and remap, while desktop drives typically have enough RAM to hold the entire set of mapping info, plus some extra for write buffering. USB 3.0 will not match native performance, but it should be close enough that you won't casually notice, unless it has to drop back to USB 2.0 speeds (in which case you wouldn't get scores even close to what you are posting).
 

razel

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May 14, 2002
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It will be the SSD/HDD that you put into the enclosure that will determine it's 4k performance. I recommend that you buy an SSD kit. The ones from Kingston come with the SATA/USB enclosure, others come with a SATA-USB adapter. The ones from Intel were my favorite since they often are USB 3.0 and report the drive name of whatever it is that you plugged in instead of renaming it.

Anyhow, you can also buy just about any Seagate Backup Plus portable drives. Those are the ones designed out of the box with a removable SATA-USB adapter. Best of luck.
 

Cerb

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Aug 26, 2000
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Now that you've mentioned controllers - is this controller located on the actual SSD or is it in the enclosure?
In the SSD. The USB bridge and USB host controller also determine performance, but no modern internal SSD should be as slow as you're benching, even with a less than perfect USB 3.0 parts combination. Your writes are especially atrocious.

FI, here is what's already been linked:
http://thessdreview.com/our-reviews/usb-3-0/angelbird-ssd2go-usb-3-0-external-ssd-review-480gb/3/
That's a run of the mill Sandforce 2.5" SSD, with an included USB bridge.

http://thessdreview.com/featured/pa...-review-incredible-gaming-on-a-flash-drive/4/
Same tests run on a big flash drive, with far less NAND bandwidth. Notice any similarities to the scores you're posting? :) Yours are actually a bit better, but with an internal SSD, they should be closer to, if not exceeding, depending on model, the above-linked 2.5" one.
 

Davste

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Jul 8, 2011
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In the SSD. The USB bridge and USB host controller also determine performance, but no modern internal SSD should be as slow as you're benching, even with a less than perfect USB 3.0 parts combination. Your writes are especially atrocious.

FI, here is what's already been linked:
http://thessdreview.com/our-reviews/usb-3-0/angelbird-ssd2go-usb-3-0-external-ssd-review-480gb/3/
That's a run of the mill Sandforce 2.5" SSD, with an included USB bridge.

Sorry, forgot to say - I've seen the Angelbird and it looks impressive but it's far too expensive. I've been digging so far and I found this:
http://www.theregister.co.uk/2012/09/15/ten_usb_3_hdd_enclosures/page6.html
Which is quite useful information. So far I know that the Akasa Lokstor X21 is the fastest enclosure. I'll probably throw in a Samsung 830 in it.
 

Cerb

Elite Member
Aug 26, 2000
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Just don't get Startech and you should be OK, IMO (I've sworn them off, now, but it always seemed there was some design or QC problem with everything I ever got of theirs, right down to cables and brackets).