gvfs incredibly slows down speed while copying files form s-ata device to another s-ata device

[ZeroBeat]

While coping some files from one s-ata device to another s-ata device gvfs slows down speed to 170 kb/sec !!!
Maybe it's a bug in 12.04 gvfs. 11.10 works fine.

from:
ata4.00: ATA-7: SAMSUNG HD753LJ, 1AA01113, max UDMA7
scsi 3:0:0:0: Direct-Access ATA SAMSUNG HD753LJ 1AA0 PQ: 0 ANSI: 5

to
ata2.00: ATA-8: WDC WD20EARX-00PASB0, 51.0AB51, max UDMA/133
scsi 1:0:0:0: Direct-Access ATA WDC WD20EARX-00P 51.0 PQ: 0 ANSI: 5

System:
DMI: System manufacturer System Product Name/P9X79, BIOS 1009 03/27/2012 (ASUS)
Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz

Best regards
Mike

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gvfs 1.12.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic x86_64
NonfreeKernelModules: fglrx
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
Date: Sat Apr 28 08:49:45 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: gvfs
UpgradeStatus: No upgrade log present (probably fresh install)

[ZeroBeat (zerobeat)]

lshw info

[ZeroBeat (zerobeat)]

hwinfo

[ZeroBeat (zerobeat)]

some additional informations:

using bash cp works as fast as expected.

Best Regards
Mike

[ZeroBeat (zerobeat)]

tested different systems under 12.04 - same behavior - speed slows down.

Best regards
Mike