Hi

I have a system with a Seagate ST320410A (20GB, 5400RPM, ATA100) hard drive on a Gigabyte GA-8SIML motherboard. Under Windows (measured using HDTach) I get throughput of around 22MB/s (DMA is enabled). However, under Kubuntu, the results are as follows:

hdparm -Tt /dev/hdb

/dev/hdb:
Timing cached reads: 1076 MB in 2.00 seconds = 536.74 MB/sec
Timing buffered disk reads: 18 MB in 3.05 seconds = 5.90 MB/sec


hdparm reports:
/dev/hdb:
multcount = 0 (off)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 38792/16/63, sectors = 39102336, start = 0

and hdparm -i shows that it is already using UDMA5.

After following the instructions in this article http://www.linuxdevcenter.com/pub/a/...29/hdparm.html, it rose to around 7MB/s

hdparm -c3 -m16 -u1 /dev/hdb

/dev/hdb:
setting 32-bit IO_support flag to 3
setting multcount to 16
setting unmaskirq to 1 (on)
multcount = 16 (on)
IO_support = 3 (32-bit w/sync)
unmaskirq = 1 (on)
hdparm -Tt /dev/hdb

/dev/hdb:
Timing cached reads: 976 MB in 2.00 seconds = 487.83 MB/sec
Timing buffered disk reads: 22 MB in 3.01 seconds = 7.32 MB/sec

I have tried this with some other drives and have achieved around 50-60MB/s in both Linux and Windows using the default settings (everything except DMA off)

Could anyone shed any light on this?

Thanks in advance.

1337_penguin