I found the standard Pegasos G4 cooling solution to be quite
noisy and annoying, especially for someone who got used to the fanless
G3! I have been experimenting a bit to change this.

I have read in other threads that some of you uses the passive Zalman
NorthBridge cooler, and I bought one of these too. To ensure that
some air gets flowing through it, I put a big Papst fan that blows air
onto it from the side at quite low RPMs, like this:

cooling.jpg

As I said, the fan is big and going at low speed and the noise has
been *greatly* reduced, and although there is no comparison to the
completely fanless G3, I surely don't get disturbed by noise anymore.

This is practically the only fan in the system. The PSU is of an ultra
quiet kind, and even though it has a fan, you won't hear it at all
even if you put your ear next to it.

I have not stress tested the CPU yet, but in normal usage (in normal
room temperature) it seems to be keeping quite cool and is working
great.

I just wanted to share my (silent) experiences ...

Thank you very much for your post. Nice job..

Hopefully at some point in the near future we'll have a passive g4 solution... until then there are nice ways of doing it..

magnetic

@takemehomegrandma

Wow, nicely done! I'm sure that will provide more than
enough cooling, and some for the rest of the board
as well. I also like your case...for a split second, I
was wondering how you'd managed to suspend everything
in mid-air.


@magnetic/general topic of G4 cards and cooling

With the different case configurations out there, I
wouldn't blame Genesi if they didn't *ever* release a
G4 card without some form of "active" cooling...how could
they guarantee it in smaller cases, with nothing but a
metal sink? Maybe sold as a complete system...but
otherwise, I doubt it would be a wise move.

In fact...I just bought a bigger heatsink for my G3
card.. Even in a giant aluminium case, the thing gets
close to 80c with dnet running!

What I *would* like to see on future "G4" cards is a
molex connector for the fan, so it can be safely removed
without desoldering anything.

Thank you guys!

Regarding the "general topic of G4 cards and cooling"; completely
leaving out any kind of CPU fan may be risky, even if the heatsink is
massive and made of copper. It will have to work cool and well in all
kinds of situations; in small and hot cases without sufficient air
flow, in hot countries during summer, on 100% CPU load 24/7, etc, etc.
But perhaps the fan can be a real silent one with high quality (not
like the one now supplied), and perhaps it doesn't have to run all the
time (or at full speed all the time), but more when it's really
needed?

Perhaps it would be possible to halt it/slow it down through software
(so that if the software crashes, it spins up at 100%)? Or perhaps it
could be controlled in HW by the CPU card itself?

It also seems like the 7447A might be slightly cooler than the version
of the 7447 currently being used. And it will have some "speed step
technology"; meaning that it will be possible to change the clock
frequency on the fly when running. I don't know if (or how) this
feature will be implemented on the Pegasos (in SW or perhaps even in
HW in some way?), but it could be implemented in a way that slows the
CPU down when it's idle or when running at only at a few % CPU usage,
and then kick in at full 1GHz (or higher ) when CPU usage peaks a
preset value.


If these two things (dynamic fan control, dynamic MHz control) gets
implemented in the right way, it could very well be possible to make a
fast G4 CPU card that runs totally mute or at least very silent in
most cases of general usage, but without taking away the possibility
to do some 24/7 RC5 crunching in a safe way during hot summer days. It
would require some development and the cards might be slightly more
expensive, but it would be worth it IMO.

Genesi, please make use of the temperature diode in the new 7447A so we know if it runs comfortably at its prefered temperature range.

Is the throttling feature of G4 currently being used?

Hi all!

As written in Motorola's UserManuals, also the old G3 (750) has a temperature sensor on die, but it's accessible only in OEM mode, so it's just a question of OS. And to read it's temperature is as difficult as a special purpose register's value reading (I mean, it's damn simple)

Bye, MarK.

@ -D-

BTW, I agree that a connector for the fan would be nice. However, I
didn't desolder anything, I simply cut the wires in the middle. So the
PCB is untouched and it will be quite simple to put the original fan
back if I want to (by soldering the wires (a lot easier than soldering
PCB's IMO) or using some kind of socket).

@ MarK

This would be very useful! -Ralph!!

Do you know if this feature is available in other OS's, like in the
Linux PPC distros available now?

@takemehomegrandma

Yeah, come to think of it, desoldering things on that expensive
PCB might be a bit extreme. Just leaving it clipped or adding a
connector later would be better.

Also some interesting ideas concerning clockspeed regulation
and CPU usage, the Pegasos/MorphOS should really take advantage
of these chip features. I also concur with MarK's statement -
desktop monitoring of the CPU temp is useful and necessary
(pretty please??).



(Oddly enough - considering the subject - it just dumped a bunch
of snow here!!! This gloomy weather has been worth something,
afterall. Maybe I should save some and send it to bPlan...and
they can adapt it into their G4 card cooling strategies)

Quote:

Which model of PSU do you use? I would like to replace my Peg-PSU with a more silent one...

Quote:

I'm at work now but I'll look it up when I get home. I bought it a couple of years ago.

Also note that these kinds of PSU's provides a very low airflow through the case, so if you are using hardware that generates a lot of heat it's often recommended that you use an extra case fan (which somewhat nullifies the benefit IMHO). For a standard Pegasos they work very well though.

Hi

Smaller and more cooler fan on the new Pegasos II G4.

Photo_030sm.jpg

Click picture for larger view !

Not delivered with the G3

Greetings !
Gunne

As I was a very long time mac user/Dev/Tech. I can told you that the temperature sensor of the G4 doesn't work as well as a true temperature sensor to monitor the cpu.
Don't forget that the G4 doesn't support temperatures likes pentium ones.
A lot of Mac users have experiment cooling solutions on G4.
Some of them are here : MacBidouille

Macleane...looking for a Peg II to find the spirit Apple has lost.

Quote:

It's a "Q Technology" 300W PSU. The model number is quite long, and I won't try to type it here. Anyway, I have had ~8 PSU's in "modern times", and this is by far the most silent one. It's *mute*!

@ Gunne

Cool! ()

How is the noise level compared to the first G4 CPU cards?

I also see that there is a fan connector on the PCB! Improvements!

Quote:

Welcome to MorphZone! If you are missing some "spirit", you have come to the right place. This is the "lost&found" site of computing spirit!

Thank you for the link BTW. However, it was in a language I don't understand! If there are some specific cooling solutions on that site that you want to enlighten us about, feel free to post a direct link!

BTW, it looked to me that Motorola kind of announced the temp sensor as a "new" feature in the upcoming 7447A, so perhaps they got it working properly now on that processor ...?

@Zylesea

Quote:

I think some may run hotter than others, I measured mine
with a temperature laser (the heatsink was getting so
hot that it burned my finger!). I added a case fan
I had laying around, and that dropped the temp from
almost 80 C to about 50 - 55 C (during dnet crunching).

From what I can gather about the net, most G3's can handle
high temps like that...but I'm going to add the bigger
heatsink and a quiet case fan, just to be safe.

Thanks for the pic, Gunne! It's good too see that connector.

@ takemehomegrandma

No, I don't know, how does it work under other OSes, I have just read most of the user manuals and programming environment manuals by motorola, and to get the temperature is very easy. Well, it's probably not very exact, I really don't know, but it should be enough for fan controling

Bye, MarK.

Quote:

What you think about that (MPC7447ACE.pdf):
TAU reports incorrect temperatures

Description:
The thermal assist unit (TAU) on the MPC7450 and MPC7455 reports temperatures between 35 to
55 degrees lower than expected.
This erratum effects only customers using the TAU. If a trip temperature is programmed into the
sensor’s control registers, the output interrupt is never received, even if temperatures exceed the
expected setpoint by up to 55 degrees (even after calibration). A control application will not be
alerted of excessive temperatures and this could lead to damage of the part.

Projected Impact:
Programmed trip temperatures will not trigger output interrupts, even if temperatures exceed the
expected setpoint by up to 55 degrees.

Projected Solution:
None. The TAU is not implemented on the MPC7447A.

Hi

Thanks for the feedback on the picture !

I haven't got time to try the new G4 yet, so cant say anything on noise-level on the fan. Will come back, but it looks nicer then the one before from my opinion. And good with connector for the wires, easier to replace fan when needed.

Have a good time !

icon_happy.gif

Gunne

Imho a better way to make such a small cooler would be the use of copper so the heat is transfered away from the die/center in the most efficient way. As you see the center of the fan is directly on top and cannot cool the hot spot directly.

Hi

I'm coming back here now regarding the new Pegasos II.

Got little time to play little.

Some good news and happy improvements have been made.

A new version of smartfirmware, v1.1.

A nice blue b, as in bplan is displayed in smartfirmware.

b.jpg

Which kind of graphicscard, and how much memory, thats detected in smartfirmware is displayed.

Seems to be more variables in smartfirmware, (booting over net ?)

If a bad template is written, a prompt appear suggesting templates to use.

Its possible to shift between G3 & G4 CPU-card.

And yes, the fan is very silent, I would like to say soundless. I dont think any decibel counter should notice anything

Well, thats just a few things, and inspiring improvements. Pegasos get better and better all the time, really nice work of bplan.

All the best!
Gunne