Hello
First of all sorry for my very bad englisch. I hope someone understand me and I will understand answers
And it is the problem:
i have abit raid bx-133 with hpt370 (ata100) and 2 same disk maxtor 40gb
At the start of system, my old kernel 2.6.17.13 find out the disks are ata100 (hdparm -i says: udma5).
I' ve installed new kernel 2.6.22.9 and at the start i have ata66...
(hdparm says udma4). Even hdparm -xdma 5 /dev/my_disk don't help.
Why?

Use hdparm -d 1 -X 69 /dev/hde. It will set to UDMA-5. You need to check the IDE cable to find out if the ribbon is 40-pin/80 wire. Normal IDE cable is 40-pin/40 wire.

Hard drives will never reach 66 MiB per second. They hover around 5 MiB to 30 MiB per second.

It depends what options you selected in the kernel. Compare your old kernel options to the new kernel options. To make sure the new kernel options are similar to the old kernel options do make oldconfig in the new kernel source directory. Then double check the new kernel options by doing make menuconfig.

[root@localhost gl]# hdparm -d 1 -X 69 /dev/hde

/dev/hde:
setting using_dma to 1 (on)
setting xfermode to 69 (UltraDMA mode5)
using_dma = 1 (on)

[root@localhost gl]# hdparm -i /dev/hde

/dev/hde:

Model=Maxtor 6E040L0, FwRev=NAR61EA0, SerialNo=E1R1BJAE
Config={ Fixed }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=57
BuffType=DualPortCache, BuffSize=2048kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=80293248
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 *udma4 udma5 udma6
AdvancedPM=yes: disabled (255) WriteCache=enabled
Drive conforms to: ATA/ATAPI-7 T13 1532D revision 0: ATA/ATAPI-1,2,3,4,5,6,7

* signifies the current active mode

This didn't work. No error but also no udma5. I wrote that in kernel-2.6.17.13 udma5 work fine without problems.
The kernels 2.6.17.13 and 2.6.22.9 i have installed as it was (without changing any option and
without recompile). I tought if it worked in old kernel it shuld be fine also in new kernel.

Other thing: this 2 kernel are not similar: some elements in old kernel are available as permanent/module and the same element in new kernel is only availabe as module.

Normally i use mandriva 2008. I tried use Mandriva One with new kernel (1CD like knoppix) and i had the same ata66. It must be some other driver or something like this...

Probably the kernel developers have placed your Maxtor model in a blacklist, so going above UDMA-4 may give you problems.

I use an HPT370 and HPT370/372. The hard drives that I use is either IBM/Hitachi or Western Digital. I have not upgraded the kernel yet. I might upgrade the kernel next, but upgrading software when the present software works fine is pointless unless the new software has features that you require.