USB transfer speed causing concern

[VBfan]

Dear VB Community,

Ever since I upgraded to VirtualBox v3, I've been concerned about its USB performance, so when I plugged a 1.5 TB drive into my Windows Guest/Windows Host VM, and waited... and waited... I decided to look into this further. None of this is complaint, however, as I think VirtualBox is a very good product indeed, and long may it continue.

I installed VirtualBox v2.04 (my pre-v3 version) on a freshly installed XP/SP2 system (1.5GHz Celeron, 1Gb RAM), created a 256MB RAM VM and did the following, copying a 415 MB file from an external drive into the VM to the NUL: device using the command prompt:

(i) Baseline copy to the NUL: device on the Host - elapsed time 23 seconds, at a calculated 144Mbit/s
(ii) Copy to the NUL: device in the VM - elapsed time 89 seconds, at a calculated 38 Mbit/s

I then upgraded to VirtualBox 3.04 and ran the following:

(iii) Copy to the NUL: device in the in the VM - elapsed time 350 seconds, at a calculated 9 Mbit/s
(iv) Copy to the NUL: device in the VM with EHCI disabled (ie now using USB 1.1) - elapsed time 140 seconds, at a calculated 24 Mbit/s

A further upgrade to VirtualBox v3.08 made no difference to the tests, nor did running with or without Guest Additions. Each test was run with a Lacie LittleDisk which was physically disconected between tests. Repeated test results were consistent to around 5%

Similar tests on a P8400 2.26 GHz CPU Dell produced similar but less extended times (quicker but still unsatisfactory), with a copy taking around fives times longer than the baseline.

So, having looked through the forums, and not found much about this, I'd really like some help...

1) Do others see these sorts of delays with USB-attached devices, and are they to be expected (and why is USB 1.1 quicker than USB 2)?
2) If no, then what can I do to diagnose and progress the underlying causes further?

Sorry about the length of this - all help very gratefully received!

VirtualBox Fan

[lukemacneil]

Yes, I am experiencing similar results.