udma from 5 -> 2 with unmatched drives

[Beemer Biker]

I noticed recently that if I mix disk drives on the same cable the Ultra Dma
Rate drops from 5 to 2. I assume this has something to do with the AMD 768
chipset for the IDE controller since I dont see the problem on a somewhat
similar equipped Intel motherboard (D865PERL)

K7D master with windows xp pro & sp2 & latest 768 amd driver Microstar web
site. Boot "C" drive is seagate ST3160023A (160mb)

If I hang a pair of 250gb WDC 2500JB on the secondary controller they both
run at UDMA-5 and the single boot drive, the seagate, runs a UDMA-5 also.

If I put any one of the WDC 250gb on the primary controller cable the data
rate on both drives drops to UDMA-2. The single drive left on the slave
stays at UDMA-5

The only reason I discovered this is because one of the drives got stuck in
PIO mode when it shared a cable with the dvd burner and I was unable to burn
a dvd from an image on that drive except at 1x speed. The DVD device
somehow got stuck in PIO mode and caused the WD250 to get into PIO mode
somehow.
I have the latest bios on the K7D master (dual athlon) and I replaced
the standard windows xp driver with the one from the MSI website but it
didnt help. Currently I took out the dvd burner and I am using one in a
firewire box until I solve this problem. It looks like I can't mix drive
types on this motherboard or chipset (amd 768)


The K7D has two 64bit slots. One is available and it is keyed for those
pci66 cards

I can get an inexpensive PCI66 32bit combo SATA and PATA controller the
will handle 1.5mb speed

I could also get a more expensive 64bit controller with SATA and PATA that
handles 3.0mb speed. I do not need RAID.

Any suggestions or recommendations?

...thanks..


--
=======================================================================
Beemer Biker (e-mail address removed)
http://ResearchRiders.org Ask about my 99'R1100RT
http://TipsForTheComputingImpaired.com
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[Rod Speed]

I noticed recently that if I mix disk drives on the same cable the
Ultra Dma Rate drops from 5 to 2. I assume this has something to do
with the AMD 768 chipset for the IDE controller since I dont see the
problem on a somewhat similar equipped Intel motherboard (D865PERL)

K7D master with windows xp pro & sp2 & latest 768 amd driver
Microstar web site. Boot "C" drive is seagate ST3160023A (160mb)

If I hang a pair of 250gb WDC 2500JB on the secondary controller they
both run at UDMA-5 and the single boot drive, the seagate, runs a
UDMA-5 also.
If I put any one of the WDC 250gb on the primary controller cable the
data rate on both drives drops to UDMA-2. The single drive left on
the slave stays at UDMA-5

The only reason I discovered this is because one of the drives got
stuck in PIO mode when it shared a cable with the dvd burner and I
was unable to burn a dvd from an image on that drive except at 1x
speed. The DVD device somehow got stuck in PIO mode and caused the
WD250 to get into PIO mode somehow.
I have the latest bios on the K7D master (dual athlon) and I
replaced the standard windows xp driver with the one from the MSI
website but it didnt help. Currently I took out the dvd burner and I
am using one in a firewire box until I solve this problem. It looks
like I can't mix drive types on this motherboard or chipset (amd 768)


The K7D has two 64bit slots. One is available and it is keyed for
those pci66 cards

I can get an inexpensive PCI66 32bit combo SATA and PATA controller
the will handle 1.5mb speed

I could also get a more expensive 64bit controller with SATA and PATA
that handles 3.0mb speed. I do not need RAID.

Any suggestions or recommendations?

I'd check using HDTach that the stated UDMA#
actually means anything at all thruput wise.