I've a very annoying issue on recent kernel (linux-3.4.2-SMP) with my main motherboard (AMD FX-8150 + 990FX - 8 cores 4.1GHz), file copy is very slow (see below). The same kernel works flawlessly on an AMD E450 2 cores motherboard.

Linux-3.2.20 works properly on this hardware.
hdparm -t gives good results on both kernels.

I've no idea where this bug come from. Do you have this issue on your hardware ? A patch is available ?


*linux-3.4.2
dd if=../in/file_8gb.tmp of=tmp.tmp bs=1024k count=100
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 132.884 s, 789 kB/s


*linux-3.2.20
dd if=../in/file_8gb.tmp of=tmp.tmp bs=1024k count=100
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 3.30793 s, 31.7 MB/s