Jack said:
Paul said:
Jack said:
"Beverly Howard [Ms-MVP/MobileDev]" <BevNoSpamBevHoward.com> wrote in
message
What os on the computer
Win xp pro, totally updated; on an Asus A8n-vm mobo.
What make/model on the gps? (there might be an alternate solution)
Magellan Meridian gold, latest firmware. No other problems with the GPS,
downloads of waypoints and tracks below 300 or 400 nodes goes ok.
Beverly Howard [MS MVP-Mobile Devices]
One question I'd have, is whether you've ever passed a stability
test on the computer. This will have nothing to do with your
USB-serial-GPS
problem, but will test whether the core of the computer works properly
or not.
Prime95 is one such tool, and it can be downloaded from mersenne.org . The
official purpose of the program, is to search for prime numbers, but the
program also happens to have a "Torture Test" option. That test carries
out a calculation with a known answer, so the test can tell whether the
CPU computes properly or not. The test uses a good sized chunk of system
memory, and tests the CPU, Northbridge of the chipset, and the system
memory. It should run for hours without reporting an error. A newly
purchased prebuilt computer should be able to pass this, or I'd send it
back to the manufacturer.
A side effect of the test, is the fact that the CPU runs at 100% load,
and warms up. Thus, the test checks the adequacy of the cooling on
the computer. If the CPU is not cooled properly, or there is a problem
with the Vcore regulator not being able to deliver full current to the
processor, that could be reflected by the computer shutting off (CPU
overheat detected), or crashing (bad Vcore voltage level).
Passing this test, will allow you to return to analysing driver problems
for USB or virtual serial port. IF you fail the test, you have other
problems to fix first.
I tried the Prime95 test, and you nailed it - it failed (twice) the same way
it has when doing a large USB -Serial dwonload.
The CPU usage goes to 100 pct in both cases for 50 or 60 seconds, then the
power cuts off.
Any suggestions about what to do about this?
Check the CPU cooling. That means, make sure the CPU heatsink is making good
contact with the CPU. Usually there is a pad or thermal paste, to take the place
of any air between the CPU and the heatsink. Sometimes the clip breaks away from
the socket, leaving the heatsink dangling. Check that the fins of the heatsink
are not plugged with dust. Check for good airflow through the computer case,
as stagnant air around the CPU, cannot cool the CPU. Fresh air must be pulled
past the area of the CPU, so the CPU heatsink can do its work.
My guess would be, that your heatsink is not in good contact.
To give an example, if the room temperature is 25C, a well cooled computer
case will be 32C to about 35C. If the air in the computer case is getting hotter
than that, make sure the inlet vents are sufficient, and the exhaust fan is doing
its job. (There should be at least one exhaust fan, in addition to the fan on the
PSU - the fan on the PSU doesn't count.)
If you have PCI slot covers, make sure they are closed. The idea is,
you don't want any "short air paths" preventing the air that is pulled through
the case, from doing its job. On my computer, I have vent space available on the
front of the computer case, near the bottom (I removed the plastic bezel, so
I could get better airflow). My exhaust fan is on the back. That means the cool
air flows through the whole computer case, before being exhausted. If all the
PCI slot covers were removed, the cool air flowing through the PCI slot covers,
would immediately whip around and leave via the exhaust fan, doing no useful
work.
My computer case also is equipped with a dust filter, and that was one of the
first things I removed. If you case has a dust filter, either plan on cleaning
it every three months, or remove it.
The CPU temperature should stay below about 65C. The reason for picking that
number, is some Intel CPUs throttle when they hit 65C to 70C. Throttling
reduces performance, and defeats the purpose of spending a couple hundred
on a good CPU. There are some processors that will become unstable around
that temperature, and that can be another incentive to improve CPU cooling.
The temperature deltas, tell you what you should be improving. For example,
if my CPU was 65C, computer case air temp was 32C, room temp was 25C, the
deltas are 33C and 7C. Since the CPU has such a large delta, the CPU cooling
would be where you'd spend the money. If, on the other hand, the
CPU was 65C, computer case was 45C, room temp was 25C, you could profitably
work on either of them. In that case, I might want to work on reducing the
computer case temp first, because the hot air is not doing the disk drive
any good. That is one reason to keep the case air temp down.
I have three sensors on my computer. I have a room temp sensor sticking out
the front grill. It is 25C. Computer case air temp is 28C. And the CPU is
29C (because I'm using a separate program to issue the HALT instruction
when the CPU is idle - for some reason the HALT that should be there in
the OS, is broken). When gaming, my CPU goes to 43C. My CPU is a 3.2GHz
Northwood P4.
Many motherboard BIOS screens, have a hardware monitor page. And sometimes
you can see the motherboard temperature and CPU temperature listed in
there. Right now, we know your CPU is messed up, so you'd only need to
check the BIOS hardware monitor page, to see how hot the
motherboard / computer case air temp is.
HTH,
Paul
