I have two disks, SSD (Samsung 830 128GB) and normal HDD (WD 1TB) and Ubuntu 12.10 installed. AHCI enabled in the BIOS. I have a problem with extremely slow copying in all directions (Samsung->Samsung, WD->WD, WD->Samsung and Samsung->WD).
Let me describe what I did:
sudo hdparm -Tt /dev/sda
The result more or less ok:
Timing cached reads: 16678 MB in 2.00 seconds = 8358.48 MB/sec Timing buffered disk reads: 1362 MB in 3.00 seconds = 453.96 MB/sec
When copying by
cp or in the midnight commander i was getting transfers only around 1MB/s!
Started reading a bit and after disabling the write cache with
hdparm -W 0 /dev/sda
The speed reaches the crazy speed of 60MB/s, wchich still is nothing for operation inside the SSD drive.
Both drives are connected to SATA 3 sockets in the motherboard. FYI: Copying from USB Pendrive goes much faster, so it looks like read speed problem. The problem doesn't occur with Windows. I paste the dmesg below:
[ 4898.720381] ata1.00: configured for UDMA/133 [ 4898.720387] ata1: EH complete [ 4898.720509] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA [ 4983.122199] ata2.00: configured for UDMA/133 [ 4983.122205] ata2: EH complete [4983.122315] sd 1:0:0:0: [sdb] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
Do you have any ideas what may be wrong?