A8N-SLI Premium PCI Bus Speed

  • Thread starter Thread starter Phil DeBecker
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Phil DeBecker

I have an A8N-SLI Premium, rev 1.2, BIOS 1006, and I observed
something strange with the speeds displayed in ntune.

If in the BIOS I leave all of the JumperFree settings on AUTO, or if I
set them to Manual with CPU clock speed 200 mhz, then ntune reports
the PCI Bus speed is 19.000 mhz. This happens no matter whether I set
the PCI Clock Synchronization to Auto, CPU, or 33.33 mhz in BIOS.

But, if in the BIOS I set the JumperFree settings to Manual and set
the CPU clock speed to 201 mhz, and I set the PCI Clock
Synchronization to 33.33 mhz, then ntune reports that the PCI bus is
running at 33.33 mhz as expected.

In other words, you have to set the JumperFree to Manual and the CPU
clock to 201mhz or more in order for the PCI clock to run at 33.33
mhz.

I never noticed anything wrong with the behavior of PCI devices --
DVD's burn and read fine, onboard sound sounds OK, etc -- but this is
curious. Are the ntune readings correct, or is this some sort of
display bug in ntune? If it is true, then by default the PCI bus is
underclocked, which is strange.

Phil D.
 
Phil DeBecker said:
I have an A8N-SLI Premium, rev 1.2, BIOS 1006, and I observed
something strange with the speeds displayed in ntune.

If in the BIOS I leave all of the JumperFree settings on AUTO, or if I
set them to Manual with CPU clock speed 200 mhz, then ntune reports
the PCI Bus speed is 19.000 mhz. This happens no matter whether I set
the PCI Clock Synchronization to Auto, CPU, or 33.33 mhz in BIOS.

But, if in the BIOS I set the JumperFree settings to Manual and set
the CPU clock speed to 201 mhz, and I set the PCI Clock
Synchronization to 33.33 mhz, then ntune reports that the PCI bus is
running at 33.33 mhz as expected.

In other words, you have to set the JumperFree to Manual and the CPU
clock to 201mhz or more in order for the PCI clock to run at 33.33
mhz.

I never noticed anything wrong with the behavior of PCI devices --
DVD's burn and read fine, onboard sound sounds OK, etc -- but this is
curious. Are the ntune readings correct, or is this some sort of
display bug in ntune? If it is true, then by default the PCI bus is
underclocked, which is strange.

Phil D.
Click to expand...

http://www.cpuid.com/clockgen.php

(Scroll down, to find the version for your board - possibly this one...)
http://www.cpuid.com/cg.php?cgid=NVNF4

See if clockgen sees the same info as Ntune.

Paul
 
http://www.cpuid.com/clockgen.php

(Scroll down, to find the version for your board - possibly this one...)
http://www.cpuid.com/cg.php?cgid=NVNF4

See if clockgen sees the same info as Ntune.

Paul
Click to expand...

Thank you for the suggestion!

I just tried it, and apparently ntune just misreports the frequencies.

With JumperFree on [AUTO], clockgen reported the PCI clock was at
33.58 mhz while ntune reported it at 19.00 mhz. With JumperFree on
[MANUAL] and the CPU clock speed at 201mhz, both reported it at 33.34
mhz.

I'm still going to keep it on [MANUAL] but at least now I know that
even on [AUTO] the clock speed isn't completely insane.

Thanks again

Phil
 
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