Heat, CPU fan speed question

D

Dave

A couple of days ago I asked a question here about a problem I was
having with a machine I was building. (I've reposted the question
below, in case anyone wants to check the parts.) People suggested that
I strip it to the bare minimum, and see if the problem was still there.
It is, even with a different power supply, and I'm going to try a new
motherboard.

But I'm really puzzled about the heat and CPU fan speed issues. The
first thing I took out was the three SCSI drives, in the cage behind
the fans in the lower front of the case. That should have cooled
things down at least a little, and made for better air flow, right?
Well, the motherboard and CPU temps didn't go up (they were around 34 C
and 45.5 C, in a 79 F room), but the CPU fan speed shot up from around
3200 rpm to over 5000. (What an annoying sound!) Not what I expected.
Then, just for the hell of it, I put the cage (with drives) back,
leaving them unconnected. The fan speed went back down. What gives??

More generally, it's pretty clear that I'm going to have to take some
parts out, for heat reasons. (Among other reasons, the room gets pretty
warm from other equipment.) It's gotta be RAM or drives. I remember,
when I was first gathering parts, asking the folks at Crucial and
Kingston how much heat the RAM would give off. They were nice, but
didn't help much. My guess is that I'd probably save more heat by
getting rid of RAM. (On the other hand, there didn't seem to be much
cooling when I took it from 2 gig down to 512 MB.) Does that sound
reasonable?

- Dave

*****
Three years ago I put together a machine, as carefully as I could.
(Everything was double-checked, static precautions observed, all
connections secure.) I didn't get to the point of installing an OS,
because the computer had intermittent problems. Right at that time my
girlfriend ripped me off of all my money and left, so I got really
depressed and just kept using my old machine.

Now I want to fix the problem, but I've forgotten almost everything I
knew about putting computers together. Plus it's been a long time,
in computer years, and technology marches on. But I'm hoping someone
could give some advice.


The machine shows no problems at all if started cold, with 15 minute
breaks in-between. (I tried 25 times yesterday, to be sure of this.)
When warm - and by that I don't mean overheated, just not turned
off for long -- I do get intermittent problems. When I start up using
the power button, the monitor gets no signal maybe 1 time in 4. (This
almost never happens when I use the reset button.) The power button
doesn't always work the same way. Also, the machine sometimes goes
to Setup and complains that it's now in safe mode because the last
time it was booted the speed settings for the processor were
inappropriate. (I never altered any speed settings.) I also seem to
remember it complaining three years ago that I had the wrong processor,

but that was a long time ago, I don't remember the exact message, and
I can't duplicate the problem.


Any ideas about what I should do? Replacing the motherboard seems like

an obvious step to me, but there might be a better idea than that. And

if I do replace it, does anyone have any suggestions about what boards
to get? As I said, it's been a long time.


Below is a list of the parts. I don't know what I had in mind,
putting so much in there - I can't remember why I thought I needed
so many drives (and both types!), or what scheme I had for partitioning

them. I'll have to take something out, as the temps get too hot when
the ambient temperature gets up there. Thanks for any help.


- Dave


Asus P4G8X Deluxe motherboard
Pentium 4 3.06 Ghz
2 meg pc2700 DDR ram from Crucial
PC Power and Cooling Turbo-cool 510 ATX power supply
Matrox Parhelia video card
Adaptec SCSI card 29320LP
Seagate Cheetah 36.7GB SCSI drive ST336753LW
2 Seagate Cheetah 18.4GB SCSI drives ST318453LW
Asus DRW-0402P DVD-R / RW Drive
Generic diskette drive
Viewsonic 19" VX900 LCD display (plus two old Trinitrons, if I ever
get this thing working)
Western Digital WD2000JBRT drive
Big case with lotsa fans
 
R

Randella

Well Dave your question is kind of loaded...

How cool do you want your system?

The case should be designed to dissipate as much heat as possible and
if designed correctly it should have some sort of air flow through it.

You are correct in assuming the extra SCSI disks created heat. Almost
any hard drive over a period of time creates heat. Although your RAM
will not produce enough heat to affect the processor.

Pulling every extra piece out of the system may not reduce the heat in
your case, it may in fact create heat pockets in the case. It's hard
to say what to remove and what to keep, not knowing the design of your
case.

As a general rule anything that plugs into the motherboard creates heat
and should be removed, except for FANS. Something else you might want
to try is cable management. Remove as many cables as you can and the
ones you must keep can be tied together and moved away from the system
components, as much as possible. This can help to dissipate heat as
well.

I hope you get it sorted.

-Randy
 
C

Clint

Personally, I'd think you'd see a lot more heat reduction yanking out your
SCSI stuff than you would by taking out a stick of RAM.

According to this fairly technical document
(http://download.micron.com/pdf/technotes/TN4603.pdf), Micron calculates a
256MB DDR module to use about 207mW of power during typical workload (page
13, if you want to jump to the summary). Even if you bump that up to 1W,
it's still pretty low.

According to the spec sheet of your larger SCSI HD
(http://www.seagate.com/support/disc/specs/scsi/st336753lw.html), it draws
10W of power at idle.

As far as the fan speeding up when you put the cage back in, the only thing
I can think of is the airflow is affected. But why your CPU fan should be
at 5000 rpm when the temp is only 45, I have no idea. On my Intel 930D
processor, at 60C, I saw a fan speed (as reported by AsusProbe) of about
2600rpm. At 5000 rpm I would expect to see it lifting the processor off the
motherboard. Seriously, I can't imagine that speed is correct, and I pity
you for the noise if it is. As it was, I stuck a Scythe Ninja cooler on my
system last night. They claim the unit can be run fanless, but only for
reduced loads. But as it turns out, my case fan blows directly over the
cooler, is exactly the same size as the fan that came with the cooler, and
is about an inch away from the cooler. So I was able to greatly reduce the
noise of my system, which made me happy.

Clint
 
M

Mxsmanic

Clint said:
But why your CPU fan should be at 5000 rpm when the temp is only 45,
I have no idea.

It may be the motherboard. I notice that when my system is booting,
the CPU fan runs at full speed; only after the boot sequence is
complete does the speed-control feature of the motherboard kick in.
If for some reason speed control is disabled, the fan will run at full
speed all the time. Remember, the power for the CPU fan (and its
speed) comes from the motherboard, not the CPU itself.
 
D

Dave

Clint said:
Personally, I'd think you'd see a lot more heat reduction yanking out your
SCSI stuff than you would by taking out a stick of RAM.

According to this fairly technical document
(http://download.micron.com/pdf/technotes/TN4603.pdf), Micron calculates a
256MB DDR module to use about 207mW of power during typical workload (page
13, if you want to jump to the summary). Even if you bump that up to 1W,
it's still pretty low.

According to the spec sheet of your larger SCSI HD
(http://www.seagate.com/support/disc/specs/scsi/st336753lw.html), it draws
10W of power at idle.

Hey, thanks for checking those values out, Clint. So I guess I'll
leave out a SCSI drive or two.
As far as the fan speeding up when you put the cage back in, the only thing
I can think of is the airflow is affected. But why your CPU fan should be
at 5000 rpm when the temp is only 45, I have no idea. On my Intel 930D
processor, at 60C, I saw a fan speed (as reported by AsusProbe) of about
2600rpm. At 5000 rpm I would expect to see it lifting the processor off the
motherboard. Seriously, I can't imagine that speed is correct, and I pity
you for the noise if it is.

I suspect that the speed is correct, because it sounds like someone's
applying the world's biggest dental drill to a fighter jet's engine
when it gets up there. A more annoying sound I cannot imagine. I'm
hoping things will magically improve once I take it apart then
reassemble.
As it was, I stuck a Scythe Ninja cooler on my
system last night. They claim the unit can be run fanless, but only for
reduced loads. But as it turns out, my case fan blows directly over the
cooler, is exactly the same size as the fan that came with the cooler, and
is about an inch away from the cooler. So I was able to greatly reduce the
noise of my system, which made me happy.

Generally I don't notice the noise too much (at the lower fan speeds),
but it feels so good when I shut the thing down!

- Dave
 
C

Clint

Check your BIOS settings, then. On my Asus MB, I've got a few choices for
the "Q-Fan control", which include silent, normal and performance.

I know what you mean about the noise. I've got a server room right beside
my cube at work, and while I don't really notice it when the doors open, I
REALLY notice it when someone finally shuts it. I just feel my shoulders
and neck un-knot.

Clint
 
J

jt3

Have you considered bad electrolytic caps on your motherboard? The board is
about the right age for the problem with the bad Taiwanese caps (I had a
Gigabyte board with the problem from the same period), and you can't always
tell by looking at them. In fact, they rely on continuous use to keep their
polarization, so not using the board for a significant period of time would
increase the problems, if they were there.

On my board, the problems started when the board was new, but got
progressively worse over about a years time until finally, amongst many
other randomly occurring symptoms, it refused to boot with more than one
DIMM slot occupied. Gigabyte replaced the caps under warranty, but yours
would probably be out of warranty by now.

Hth,
Joe
 
R

Rod Speed

jt3 said:
Have you considered bad electrolytic caps on your motherboard? The
board is about the right age for the problem with the bad Taiwanese
caps (I had a Gigabyte board with the problem from the same period),
and you can't always tell by looking at them. In fact, they rely on
continuous use to keep their polarization, so not using the board for
a significant period of time would increase the problems, if they
were there.

On my board, the problems started when the board was new, but got
progressively worse over about a years time until finally, amongst
many other randomly occurring symptoms, it refused to boot with more
than one DIMM slot occupied. Gigabyte replaced the caps under
warranty, but yours would probably be out of warranty by now.

Warranty time is irrelevant when its supplied defective.
 
J

jt3

In principle, but not necessarily in practice unless you don't care how much
time and trouble you expend trying to get them to cooperate.

Joe
 
R

Rod Speed

jt3 said:
In principle, but not necessarily in practice unless you don't care
how much time and trouble you expend trying to get them to cooperate.

Doesnt take much to **** them over in the small claims court.
 
J

John Doe

Rod Speed said:
Doesnt take much to **** them over in the small claims court.

The word "practice" means "in the real world" not Rod Speed's
tough guy fantasy land.
 
R

Rod Speed

The word "practice" means "in the real world"
not Rod Speed's tough guy fantasy land.

Even someone as stupid as you should have noticed
that the small claims court is part of the real world.

You dont necessarily have to use it either, just the threat to
use it if they dont do what the law requires is usually enough.
 

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