Dimension 8300 SATA compared to Dimension 8400 SATA

So I finally got ahold of a Dimension 8400 for some comparison testing
with my 8300. (Thanks to Ben Myers!) I may be crazy, but I've had the
sneaking suspicion that the 8400 is what I should have waited for,
even though my 8300 got a lot better when I dumped the Prescott CPU
for a Northwoods version.

Right away I noticed a few very obvious differences..the LGA775 CPU
socket, more SATA ports, Intel 925 chipset (as compared to the 8300's
i875), gigabit ethernet and a PCIe graphics slot.

When I got into system setup, I noticed something else that is very
different from the Dim8300 series. The 8400 has several options--RAID
autodetect/AHCI, RAID autodetect/ATA, RAID on, and Combination. Dell
says the factory default is the AHCI mode.

Windows XP setup on the 8400 loaded the "iastor" driver for disk
storage while the 8300 used the "atapi" driver.

On the 8300, none of these options exist in setup. In fact, as far as
I can tell, the Dimension 8300 runs its SATA ports in ATA mode all the
time.

What I'd like to know is what kind of a difference this might make in
terms of performance? It seems that having the ability to use AHCI
mode enables some more advanced SATA features, such as NCQ that are
simply not available when the system treats the SATA ports as ATA
devices.

William

I would expect performance to be better than the 8300, but I cannot quantify.
The Dimension 8400 has a more advanced chipset than some of the "newer" Dell
systems with silver decor and 915 chipset... Ben Myers

On Sat, 21 Jun 2008 06:51:03 -0700 (PDT), "William R. Walsh"
<> wrote:

>So I finally got ahold of a Dimension 8400 for some comparison testing
>with my 8300. (Thanks to Ben Myers!) I may be crazy, but I've had the
>sneaking suspicion that the 8400 is what I should have waited for,
>even though my 8300 got a lot better when I dumped the Prescott CPU
>for a Northwoods version.
>
>Right away I noticed a few very obvious differences..the LGA775 CPU
>socket, more SATA ports, Intel 925 chipset (as compared to the 8300's
>i875), gigabit ethernet and a PCIe graphics slot.
>
>When I got into system setup, I noticed something else that is very
>different from the Dim8300 series. The 8400 has several options--RAID
>autodetect/AHCI, RAID autodetect/ATA, RAID on, and Combination. Dell
>says the factory default is the AHCI mode.
>
>Windows XP setup on the 8400 loaded the "iastor" driver for disk
>storage while the 8300 used the "atapi" driver.
>
>On the 8300, none of these options exist in setup. In fact, as far as
>I can tell, the Dimension 8300 runs its SATA ports in ATA mode all the
>time.
>
>What I'd like to know is what kind of a difference this might make in
>terms of performance? It seems that having the ability to use AHCI
>mode enables some more advanced SATA features, such as NCQ that are
>simply not available when the system treats the SATA ports as ATA
>devices.
>
>William

ahci is faster!


William R. Walsh wrote:
> So I finally got ahold of a Dimension 8400 for some comparison testing
> with my 8300. (Thanks to Ben Myers!) I may be crazy, but I've had the
> sneaking suspicion that the 8400 is what I should have waited for,
> even though my 8300 got a lot better when I dumped the Prescott CPU
> for a Northwoods version.
>
> Right away I noticed a few very obvious differences..the LGA775 CPU
> socket, more SATA ports, Intel 925 chipset (as compared to the 8300's
> i875), gigabit ethernet and a PCIe graphics slot.
>
> When I got into system setup, I noticed something else that is very
> different from the Dim8300 series. The 8400 has several options--RAID
> autodetect/AHCI, RAID autodetect/ATA, RAID on, and Combination. Dell
> says the factory default is the AHCI mode.
>
> Windows XP setup on the 8400 loaded the "iastor" driver for disk
> storage while the 8300 used the "atapi" driver.
>
> On the 8300, none of these options exist in setup. In fact, as far as
> I can tell, the Dimension 8300 runs its SATA ports in ATA mode all the
> time.
>
> What I'd like to know is what kind of a difference this might make in
> terms of performance? It seems that having the ability to use AHCI
> mode enables some more advanced SATA features, such as NCQ that are
> simply not available when the system treats the SATA ports as ATA
> devices.
>
> William

Hi!

> ahci is faster!

I decided to look into things a little deeper, so I did two DBAN runs
(writing zeroes), one with the SATA controller operating in AHCI mode
and another with it running in IDE mode.

Yes, I know DBAN is probably not a good benchmark. However, it should
write to the disk as fast as possible. And I'm not sure that it didn't
see right through the settings, as both times it identified the disk
as being "SCSI" (something that I've seen with other SATA controllers
running in AHCI mode).

The speeds differed very little between IDE and AHCI modes. AHCI was
just a little bit faster.

Now that the system is up and running with Windows XP SP3, I can see
that there is quite a performance gap between my Dim8300 and the 8400.
I'm not sure what the difference is, but the LGA775 Prescott 3.4GHz
Pentium 4 is downright snappy where the Socket478 version in my
Dim8300 never was. And even though the Dim8300 improved drastically
with the switch to a 2.8GHz Northwoods P4, I still think it should be
somewhat snappier than it is.

The Dimension 8400 has also never increased its fan speed, even under
constant 100% processor load. The Northwoods P4 improved the behavior
of my Dim8300's fan, but it still seems that I just have to look at it
to make the fan speed go up.

Since my Dimension 8300 is nicely equipped, and set up to do what I
want (it's primarily used for running VMware virtual machines), I'm
going to keep it set up and running the way it is. I just wanted to
see the difference between 8300 and 8400, and answer the long standing
question as to what I should have purchased. Evidently I would have
been happier if I'd waited, but now I have both. :-)

William