Thanks Paul for your usual quality explanation!!

MikeSp
-----------------------
"Paul" wrote in message
...
In article , "Michael S."
wrote:

While dinking around in the BIOS of this new build, I noticed that in
the
BIOS under MAIN, that the Primary IDE Master (WD2000JB) had 32 bit data
transfer [Disabled] (this is my backup drive) and could find nothing
about
said 32 bit data transfer in regard to the RAID 0 Raptors on this
system.
Device Manager, Disk Management, Aida32, PC Wizard and CPUz all do not
show
any details about the rate of data transfer on either the IDE or SATA
HDD's.
Should this 32 bit data transfer be enabled or is it important or too
late?

MikeSp

http://www.rojakpot.com/freeBOG.aspx
http://www.rojakpot.com/showFreeBOG.aspx?Lang=0&bogno=3 "32 bit transfer
mode"

I think the 32 bit setting is an optimization for PIO mode only.
DMA must be doing something more efficient than transferring
either 16 bits or 32 bits at a time. To get the best performance,
data should be travelling in DMA bursts, like 8 PCI words at a
time, for example.

I looked in the ICH5 datasheet. This is the closest mention of a
32 bit mode that I could find. Since probably all your drives are
operating in DMA mode, that setting hardly matters.

"PIO 32-Bit IDE Data Port Accesses
A 32-bit PCI transaction run to the IDE data address (01F0h primary,
0170h secondary) results in two back to back 16-bit transactions to
the IDE data port. The 32-bit data port feature is enabled for
all timings, not just enhanced timing. For compatible timings, a
shutdown and startup latency is incurred between the two, 16-bit
halves of the IDE transaction. This guarantees that the chip selects
are deasserted for at least two PCI clocks between the two cycles."

If you run a drive in PIO mode, then the 32 bit setting may help.

HTH,
Paul