LeeG said:
Hi paul.
On all cards the fans were/are running okay and no temp issue, (this was one
of my first concerns - checked the whole system). MY mobo can be overclocked
but not doing that right now. Need to stabilise the graphics card before
attempting anything like that. I can't find any tech data on the psu I have.
With the graphics card drawing its power from the mobo instead of having a
seperate molex power supply, is this what the advice concerning a new power
supply is based on. Too much power being drawn from rail one.
Your 12V2 is 7.4A (that is the 2x2 cable powering the processor).
Your 12V1 is the rest, which is 4.5 amps. Only 2.4 amps of that
(video card plus fans) comes through the main power supply cable. The
rest of the current is via Molex hard drive power connectors and the
like.
The currents involved are pretty small.
If the power supply wasn't working properly, and was delivering abnormally
low voltage, or was placing electrical noise on a voltage rail, that
could cause problems. But the thing is, you note video corruption,
without the computer crashing. Which suggests a problem local to the
video card itself. You would expect a wider variety of symptoms,
like other things complaining about power. (A hard drive, for example,
will spin down and spin up again, if it detects even a slight drop
in the 12V feeding it.)
But without any other symptoms other than glitches on the video card
output, I'd have to assume it is some problem with just the video card.
And drawing 1.9 amps through motherboard copper tracks, shouldn't be
an issue - I don't think this is going to be the result of a motherboard
design issue.
You could use a multimeter to verify the voltages from the supply if
you want, but most people end up unsatisfied after doing those measurements.
(Problems are seldom detected with just a multimeter.)
I have a clamp-on DC ammeter, and that is handy for detecting accidental
shorts or overloads. It is a nice instrument, but at about $300, isn't
a good investment for a home repair situation. A $20 multimeter from
the hardware store is what most people can afford, and making only
voltage measurements with one, doesn't usually lead to an "aha!" moment.
My clamp-on ammeter is contactless - you clamp it around a bundle
of wires, and it tells you how much current is flowing. In about
30 seconds of measurements, I have a pretty good picture of current
flow from 3.3V, 5V, 12V and so on. Measuring the voltage may sometimes
show a power supply with a problem, but I wouldn't expect it to be that
easy most of the time.
Do you have any other symptoms to add ? Are the BSODs ? Anything showing
up in the Event log ?
Perhaps it boils down to you getting two bad cards in a row.
Another question for you - did you remember to uninstall the 7300GT driver,
while the 7300GT was still in the computer ? Then, install the new video
card, and install a driver for it ? If you've been flipping cards in and
out, without changing drivers, I can't imagine the software being very
happy.
I learned that the hard way. I kept changing video cards, leaving the
old drivers in, and just installing over top when the next video card
came along. Then one day, I couldn't get one of the acceleration settings
to work on my video card any more. I tried driver cleaners, I tried
uninstalling drivers and reinstalling them, and nothing fixed it. I
had to reinstall the OS to clean up the mess. Now, I'm a bit more
careful, to remove the old driver, before installing the new hardware.
Paul
GT220 = 22.9W max! 22.9W/12V = 1.9A from 12V1