In article , "Johnny"
wrote:

This is a repost as the other didn't appear so if it pops up
twice, sorry.

I posted a while ago the dismal performance I'm getting with
this board and a Prescott 3.0ghz cpu with 2 x 512K crucial
2-2-2-5 ddr400 memory. I've noticed the passmark cpu tests give
significant differences but not entirely sure if that's not
unusual - is it possible the cpu or motherboard is faulty
even though the system works albeit relatively slowly. This
thing has me totally flummoxed and perplexed. I've swapped out
a power supply from another machine with no change (don't know
why but thought it might be a power issue). I haven't got access
to another 800FSB cpu to compare and not sure I'll get any sense
out of the tech support as it is actually working which is
frustrating in the extreme. If I select turbo mode the board dies -
it literally blacks out completely requiring a hard power off
to get bios back with the post message that overclocking failed???
I'm really getting ****ed off with this now - is it likely the
cpu or mainboard are faulty or just a combo of the two, who knows?

Are you talking about Passmark giving different results from
repeating the Passmark test ? Or are you talking about comparing
Passmark from your current machine, to a previous slower machine,
or comparing to the Futuremark database ?

With respect to your turbo mode setting, turbo requires the use
of CAS2 memory, which you've got. So, it should have worked.
A "black out" is what happens with CAS2.5 or CAS3 memory, when
turbo is selected.

How many ways are there to make a slow processor:

1) Internal CPU cache has ECC protection. If the internal cache
has bad bits in it, a single bit in error can be corrected
by the ECC checker, but at the price of extra cycles to
attempt to correct the data.

I don't know whether Memtest86 can detect this kind of
fault or not.

2) Intel processors have thermal throttle. In the case of the
Prescott, the processor reduces the internal instruction rate
when the die temperature reaches 70C. If the CPU die is not
making good contact with the heat spreader on the top of the
chip, it might be possible for the die to be hot, yet the
heatsink won't be that hot. There is a thermal paste inside
the processor, between the top of the die and the heat
spreader, and if that paste was missing, your performance
could drop.

3) ACPI has an option to reduce the processor clock rate. But
I doubt that is doing anything in this case. ACPI might
use this option, when the processor is idle, to reduce the
processor operating temperature. During benchmarks, the OS
would turn this off again.

4) Many Northbridge chips have throttle capabilities for the
DIMMs. See section 5.5 (pg.140) of this document, for features
of the 875 Northbridge regarding protecting the DIMMs against
overheat. I doubt Asus bothered with thermal sensors next to
the DIMMs, but there is still the software method:

http://developer.intel.com/design/ch...s/25252502.pdf

"The number of hexwords transferred over the DRAM interface
are tracked per row. The tracking mechanism takes into account
that the DRAM devices consume different levels of power based
on cycle type (i.e., page hit/miss/empty). If the programmed
threshold is exceeded during a monitoring window, the activity
on the DRAM interface is reduced. This helps in lowering the
power and temperature."

5) You could be experiencing an "interrupt storm". There have been
motherboards in the past, where a particular PCI chip on the
motherboard keeps asserting its IRQ, causing the interrupt
handler to be invoked needlessly, and sucking performance from
the machine. Looking at performance counters might identify such
a problem. (There is one report in Google against the Promise
20378, so see if you can run with that chip disabled, then
run Passmark again.)

6) The PCI Latency Timer setting could influence performance.
A setting lower than 16, could make I/O slow, but the BIOS
on this machine doesn't allow such low settings. Lower settings
promote "fairness" between peripherals, so a sound card can
still get data while a disk drive is doing burst transfers.
A high setting might allow a better disk benchmark, at the
expense of general usability of the computer.

I haven't had too much luck using performance counters in Windows.
I've read that there are all sorts of fancy metrics in Windows, but
maybe you need a plugin/snapin to see them ? I still don't know
what the missing ingredient might be.

It may be easier to see some of these performance counters in
Linux.

The toughest part of your problem, will be finding baseline
numbers for exactly what your combo of hardware should be
doing. Does Futuremark collect enough data, to make sure
the BIOS settings that affect memory performance are the
same, when you compare to other hardware ? If Passmark is
not collecting info on whether PAT is enabled, for example,
that might make a difference to benchmarks.

I tried researching in two directions. I looked for benchmarks
that are a bit simpler than Passmark, and for the CPU, there
is the HINT benchmark. But all knowledge of it is gone from
the .gov site it was on, and even web.archive.org has no
copy of the site. I also tried to find info on performance
counters, and didn't have much luck there, either. Intel
has a $$$ program called Vtune, which is a profiler used by
software developers, but that isn't free.

I was hoping by using free tools, we could compare machines,
and see if you really are slower than other comparable machine,
and what part of the machine is slower. Some things you can
try:

1) memtest.org has version 1.4 of memtest86 available. It is
presumably the same as the other versions, when it comes to
measuring bandwidth. I get L1=8KB=22940MB/s, L2=512KB=19571MB/s,
and main memory is 2955MB/s. Memtest claims PAT is enabled
on my machine. I have a 2.8C Northwood, 2x512MB 2-2-2-6 RAM,
running at stock speed.
2) ftp://ftp.heise.de/pub/ct/ctsi/ctiaw.zip
This runs from a DOS window, and reports a few settings.
It is a way to verify that PAT is enabled. Mine says "fully
enabled".

http://abxzone.com/forums/showthread...ighlight=ctiaw

It also reports two values at the top of the screen, the
"sleep" speed and the "load" speed. On my 2.8C, the values
reported are both close to 2800MHz. It seems other processors
are using different frequencies for this, but I don't know
why. It could be the ACPI throttle feature, not sure.

As for performance counters, booting a copy of Knoppix or some
other Linux distro, might give access to more info than you can
get easily from Windows. If I do "vmstat 5" in a console
window, it says I get exactly 1000 interrupts per second.
(The number will be related to clock tick interrupts, as in
this scenario the system was idle, except for vmstat running.)
If I had a defective 20378, that number would undoubtedly climb.
I don't know how much work it is to get Windows to display
the same stat, whether it is total interrupts, or interrupts
per peripheral device.

HTH,
Paul