'dd' performance has dropped dramatically.

I opened this in "Apple.com > Support > Discussions > Mac OS X Technologies > Unix" under this thread...
http://discussions.apple.com/thread.jspa?threadID=332597
But, I though I'd cross-post it here as well...
==============
Has anyone else noticed this?
I need to make "Forensic" copies of drives for my work. Thus I use 'dd' to make the copies of the evidence.
So, I use 'dd if=/dev/disk3 of=/Volumes/Foresics/disk3.dd bs=1m' to do the copy.
Though depending on the buffer cache of the source drive, you can use a larger/smaller 'bs' to match.
Last year, I used 10.4.3 to 'dd' a 40GB drive with a 1 MB cache in 80 mins (or so). Yesterday, I imaged a 40GB drive with a 1 MB cache in 14 hours!
Things I tried....
1) "Disk Utility" to make a 'dmg' = 75mins
2) "mount read/only" to make a tar = 90mins
3) "dd" to make a forensic image = 14 hours.
Since "Disk Utility" to 75 mins to make a 40GB dmg of an NTFS partition, it still did a full read of the disk. I know the USB IDE adaptor was running at USB2 speeds, and there was no other processes running besides the 'dd' (no CPU/Mem/Disk usage noted apart from the active copy process.)
The problem is only with 'dd', regardless of blocksize settings I can't get more than 70MB/min when I used to get 500-800 MB/min.
So, anyone else seen this?
Scott
PowerBook G4   Mac OS X (10.4.4)  

I've not ever used dd, but should this prove to be a common problem please report it to Apple in Bug Reporter - it's a serious performance issue!
https://bugreport.apple.com/cgi-bin/WebObjects/RadarWeb.woa
Matt

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