I have similar problems. $ sudo hdparm -tT /dev/sda
/dev/sda: Timing cached reads: 3510 MB in 2.00 seconds = 1754.82 MB/sec Timing buffered disk reads: 264 MB in 3.02 seconds = 87.49 MB/sec hdparm -i shows it in udma6 mode. BUT, copy large files shows a transfer rate of ~5MB/s. Occasionallly, it ranges from 2MB/s to 10MB/s. I tried some other copying tests and found interesting results. My WD 750gb SATA drive has both ext3 and NTFS partions on it. Since I wasn't sure what was the limiting factor that is make the transfer so slow, I copied a 500MB file in/out for both NTFS and exts into/out of /dev/shm, as it can be assumed the RAM disk has the ultimate read/write speeds. Here are the rough results: NTFS to NTFS: full speed (~70-80MB/s) NTFS to /dev/shm: full speed /dev/shm to NTFS: full speed ext3 to ext3: SLOW (~5MB/s) ext3 to /dev/shm: SLOW /dev/shm to ext3: FULL SPEED That was the surprising part. Copying from RAM disk to ext3 gave me full speed! So I conclude that the problem is in the read speed. Write speed is perfectly fine. FYI, my ext3 is already mounted with the noatime option. Any comments? -- Slow SATA performance https://bugs.launchpad.net/bugs/119730 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
