hard disk performance issue in dual boot with FC7 and Windows

[narsins]

Hi. I am currently running dual booting os with FC7 and WIndows Server 2003 x64 on 150GB WD raptor.
My motherboard is AB9 Pro (which has ICH8R, Jmicron, and Sil3132)
The hard drive is connected with ICH8R. I am explainning all these because it seems a complicated problem
for me to figure out when I tried to research about the problem.

I have experienced that hard drive performance is significantly slow down and instable when i was using windows. I ran HD tune to see the performance. Frequently, it dropped as near as 1.2 MB/sec.
(It used to work like max 90MB/sec and min 35MB/sec)

First time, I doubt that installing FC7 on same disk may cause this issue.
So, I erased the all partitions allocated for FC7 on disk management tools in windows and
re-ran the benchmark right away. Then, the hard drive ran fine after that.

My second doubt was repartitioning ntfs. So, I formatted all partitions and re-install windows and
check that it was ok. I installed FC7, but not configured for user login. The hard drive was running fine.
But, after everything was set up for FC7, the hard drive had the similar instability issue in windows.
Now, the performance does not drop such low, I still see the instability on the graph when benchmarked.

Does anyone have similar problems or have knowledge about this issue?

[glennzo]

No similar problems. You can run hdparm to check the disk performance in Linux. That would give you something to compare with that other OS. In that other OS making sure DMA is set to on helps, providing it's available for the drive.

Here's sample output on my laptop:
[glenn@toshiba ~]$ sudo hdparm -t /dev/sda
Password:

/dev/sda:
Timing buffered disk reads: 130 MB in 3.02 seconds = 43.09 MB/sec
[glenn@toshiba ~]$