ShadowTek wrote:
> OK, now I have a new problem. The BIOs on my motherboard are extremely
> limited and do not allow me to disable to RPM monitoring of the CPU
> fan. I think this will result in my BIOs preventing my computer from
> starting in I install the fan that comes with the AC Freezer 64 Pro.
>
> That's too bad, since I was reading a lot of positive reviews, and I
> was looking forward to using it.
>
> So, in light of this limitation, what cooler would you recommend?
>
> I just used SpeedFan to push my CPU fan to 100%, and the RPMs topped
> out at about 5600. So, I guess I need something that can do at least
> that.
Do you have details, as to what RPM range the motherboard doesn't
like ?
The manual I could find here, for MS-7093, doesn't go into details for
the hardware monitoring. (Apparently, there is more than one motherboard
with that number, and I downloaded this, just to see how bad the BIOS
screens are.)
http://download2.msi.com.tw/files/do.../E7093v1.6.zip
It almost looks like the CPU fan header is a 3 pin. The AC Freezer 64 Pro
uses a four pin connector (according to the description on Newegg). Which is
not a problem.
--------- (Keying tab) Four pin header
X X X X
PWM RPM +12 GND
--------- (Keying tab) Three pin header
X X X
RPM +12 GND
If you plug a four pin fan into a three pin header, the PWM pin won't
have an electrical connection. A floating PWM allows the fan to
run at full speed, so should not interfere with normal operation.
In principle, a four pin fan should not be fed a variable voltage on
the 12V pin. So you'd want to keep the fan running at 100%, so that
the motherboard feeds 12V to it. (The reason for this, is the PWM
uses a transistor inside the fan hub, and to help keep the transistor
saturated, it helps if the fan is being fed full voltage. The condition
they're trying to avoid, is having the transistor partially conducting,
which increases the internal heat in the transistor.)
The first review on Newegg right now, mentions that the AC Freezer 64 Pro
ran at two speeds for the reviewer. It ran at "450 RPM" and "2400 RPM".
Maybe this had something to do with motherboard fan speed control, but the
comment is a bit strange.
http://www.newegg.com/Product/Produc...82E16835185125
If I was expecting trouble, I'd probably buy and keep handy, a fan power
adapter. What this thing does, it draw the 12V from the Molex disk
drive connector. (You may need to purchase a Y cable as well, to get
enough connectors to plug this in.) There are two fan connectors on this.
The middle one goes to the three pin on the motherboard, and delivers
the RPM signal (to keep the BIOS happy). The right hand one, goes to the fan.
The purpose of using this, is so that the motherboard fan control, cannot
drop the fan speed (and the 12V level). And the fan will run as close to
100%, as it is capable of. That gives you 2400 RPM, and one would hope,
enough to pass the RPM minimum of the motherboard. (I have one motherboard,
where 1800 RPM is the minimum. Modern motherboards are a bit more intelligently
designed, and have a lower minimum than that.)
"Rosewill RCW-311 12 inch Fan Power Supply Cable - Retail"
http://www.newegg.com/Product/Produc...82E16812119149
"APEVIA 1 x 4Pin To 2 x 4Pin Cable" - Y cable for disk drive power
http://www.newegg.com/Product/Produc...82E16812201006
The minimum RPM that the hardware monitor provides, is determined
by the "scaler register". It sets the time base for the speed
measurement. Some motherboards don't crank this to accept low fan
speeds. My motherboard has a couple notches left, which would allow
it to sense a slower fan, if the BIOS had been set up that way.
Speedfan is pretty clever, in how it uses the scaler register.
Speedfan "autoranges", changing the scaler register until the
bits collected in the measurement register occupy a significant
part of the dynamic range of the register.
Other programs are not as clever. MBM5, the Motherboard Monitor
program, doesn't change the scaler, but works with the value
already set. And what that means, is if used by itself, MBM5
might read zero for a fan. Then, when Speedfan is used, it
will get the reading. Then, if you used MBM5 again, suddenly
it would be working (because Speedfan adjusted the register).
Of course, none of what happens in Windows, helps with the
BIOS check of fan speed during POST. The above is just to point
out some of the things that can happen with Windows programs,
versus the hardware monitor chip.
If you wanted to use the AC Freezer 64 Pro, having an adapter cable
handy, may give you an option to help it run full speed. If
it turns out to handle the lower fan speed without a problem,
then perhaps the adapter cable would not be needed.
There is yet another alternative. You can take a separate fan,
and plug it into the CPU fan header, to keep the BIOS happy.
You would then need a means to power the real CPU fan, as the header
would be occupied by an RPM equipped fan, whose purpose was
just to keep the BIOS happy.
(Examples of some small fans that spin fast. The whine from one
of these would drive you bananas. The fastest one here does
8000RPM. I have an older model of their 40mm fan. )
http://www.actrx.com.tw/datasheet/20...0_I_12-24v.pdf
Paul