Bill Hillman wrote:


New CPU installed and running this morning. Did a little playing
around with overclocking the CPU. Was able to hit 4Ghz pretty
easily! Stock retail cooler. I could not find a way to adjust the
CPU voltage on this board, settings are really limited. Was
pleasantly surprised. The odd thing is I could not change the
multiplier to more than 19x, probably a BIOS glitch since it would
jump to 5x when I selected 19.5x. So I bumped the FSB after that. It
would actually post at 4200Mhz but lock right after BIOS screen.
4050Mhz got into windows boot but locked before reaching desktop. I'm
sure with some fancy cooling and more voltage it could probably go a
little higher. Maybe dig out the old water cooler thats been sitting
in a box for the past 6 yrs. =)

Someday when I need the extra power and more programs take better
advantage of multicore CPUs I'll replace the mobo with something a
little more OC friendly and unlock the extra cores.

Thanks,
Bill


I don't see an option listed in the BIOS for that.

MicroATX boards aren't always set up for overclocking. That tends to
be a feature of full sized ATX motherboards. But even then, they can be
missing the feature needed to adjust Vcore. I have a full sized ATX
motherboard, which only cost $65, and it had no voltage adjustment.
But the regulator chip on it, turned out to be quite nice anyway, and
the regulator had an "offset" pin on it. By doing a single resistor
change to the motherboard, I could get a 0.1V boost (that's all I tested).
It wasn't enough to make the thing stable at a 33% overclock, but it was
close.

The Vcore regulator is power limited on your board, and that isn't
one of the Asus 140W motherboards. Power dissipation in Vcore rises
rapidly, if you're volt modding, and you want plenty of power head
room if doing so. Power is proportional to V**2, so if you go from
1.3V to 1.4V, the relative power change is 1.4*1.4/(1.3*1.3) or 1.16x.
In some overclocking situations, by adjusting the voltage, you can
easily draw 50% more than the rated TDP of the processor. The most
famous case, was probably overclocking the Pentium D 805 to 4GHz,
where some people laid their motherboard on a foam plastic support,
and the motherboard melted the foam :-) That was a power draw of over
200 watts. So if the motherboard is kinda power limited on Vcore to
begin with, you don't want to push it too far.

If you want instant feedback as to what your changes are doing,
try sticking a finger on the MOSFETs around the CPU socket.
They'll give you some idea how stressful the operation is.
On one of my boards, I had to stop, because the MOSFETs were
beginning to heat up. MOSFETs do have a Safe Operating Area, and
do have the option of going into thermal runaway (in the sense that,
the channel resistance begins to go up, so the heating process of
the MOSFET accelerates - the MOSFETS "go limp" when they get hot).
It means near the end of the power limit, the MOSFET temperature
curve gets steeper. MOSFETs have been known to get hot enough,
to melt the solder underneath. That's for the ones that don't have
a heatsink (because the designer wasn't counting on a 200W load).

Your board has a three phase regulator, and no heatsinks.

http://images10.newegg.com/NeweggIma...131-014-03.jpg

Based on that picture, your best option would be a CPU cooler that
blows downwards. The "spill air" from the CPU cooler can be used to
keep adjacent stuff cool.

Paul