Archived from groups: alt.comp.periphs.mainboard.asus (More info?)
In article <Q_6dnXQSTcaHij_fRVnemail@example.com>, "Richard K Rabbat"
> How would one know if AGP/PCI lock works or not?
> I have a Athlon 64 3500+ Venice core and would like to overclock it. What
> would be good setting to do so?
> My motherboard is a A8V deluxe Version 2.00 (supposed to be anyway). And I
> can't get AGP/PCI lock to work, what am I doing wrong?
The only way to really know for sure, is to use a frequency counter
and measure it.
This device ("PC Geiger") will measure the PCI clock. I'm not aware
of a product that does the AGP clock (unless some video card has
a way of measuring the AGP clock frequency - the video card could have
at least one quartz crystal on it, that could be used as a time base).
Most people will rely on Windows utilities that can read the settings
used on the clock generator chip. Depending on the chipset, either
all the clock signals come from the clockgen chip, or a good number
of them are generated (derived) by the chipset itself. In the
case of Athlon64, for example, I believe the DRAM clocks come from
the processor, so the clockgen doesn't do as much stuff as it used to.
(Please read the FAQ for more information about the use of
ClockGen with these particular mainboards.) CG-ICS950405 "
The FAQ says to set "Performance Mode" to [Auto] in the BIOS, only
if you wish to actually change the clock settings while in Windows.
Leaving Performance Mode set to something else, will likely not
affect the ability to read out the current settings.
This is your clock generator chip. It could be that the AGP clock
is derived from one of the HTT clocks, inside the Northbridge.
The reference to "asynchronous bus" for K8T800pro in this chart,
could be the indication that the AGP is independent (locked) when
compared to the HTT clock (200MHz). It also means the clockgen
program has to be able to correctly read how the logic is set up
inside the K8T800pro Northbridge.
A real good indication, of course, is when your video card goes
nuts. With older AGP cards, the clock can be raised to 100MHz and
the card can still function. Some of the newer, higher power cards,
seem to be limited to about 75MHz - YMMV.
For PCI clocks, a reasonable limiting value is about 37.5MHz.
Depending on the length of the PCI bus, and whether the PCI chip
uses the bus clock for media purposes, will determine whether you
can get closer to 40MHz on the PCI or not.
When messing with clocks, it pays to visit the private forums and
try to find info on disk corruption. Some SATA devices seem to be
adversely affected by overclocking, and IDE drives can have similar
issues with other bus clocks. At the very least, have a backup copy
of the hard drive available, in case your boot disk gets corrupted.
My favorite method, is to boot with Knoppix (Linux distro), as it
will boot from a read-only CD and no hard drive, and is