hdparm shows poor performance on cached reads for PATA drive

[Konstantin Svist]

Konstantin Svist wrote:
> I have an older laptop (HP ze4400 series) with a PATA hard drive.
> When I check hdparm -T /dev/sda in Fedora 7 or 8, it shows me 
> performance of ~180MB/sec
>
> When I use a boot CD (gparted/clonezilla) to check the speed (by the 
> way, it uses the old style /dev/hdc, instead) - it tells me the 
> performance is upward of 400MB/sec
>
> The buffered speed seems about the same in either case at ~30MB/sec. 
> (I've tried enabling/disabling various settings via hdparm, while in 
> boot CD mode)
>
> Why is this happening and is there a way to fix it (without reverting 
> to /dev/hdc)?


*bump* since I got no replies from last time
Just ran another test: in F8, I get 123MB/s on cached reads, 28.55MB on 
buffered reads. When booted into Knoppix 5.1.0, cached reads say 
210MB/s, and buffered reads fluctuate between 15MB/s and 20MB/s.


Thanks in advance for any info


P.S yes, old message should've said /dev/hda, not /dev/hdc :)