"los" said:
I recently upgraded some parts of my computer.
I have a leadtek Winfast a350 based on Nvidia 5900 XT 128 meg card,
AMD 2.6 Barton
Asus a7v8x-x MB
1 gig Corsair 300 mhx SDRAM
Antec 350 watt power supply
Windows XP
When I don't have Nvidia's drivers installed or I have Hardware acceleration
set to 0 the pc runs fine. With the newest nvidia drivers installed and hw
acceleration set past 0, the computer reboots when I scroll down on a web
page in Internet explorer, (or sometimes when I move a window around on the
desktop).
I have just recently formated the HD and re installed XP. The mem, and the
video card run fine on another MB. Any ideas?
It could be a power problem, or it could be an AGP slot problem.
This sounds like a Herolchi 350W supply, done under contract to
Antec. 3.3@20A, 5V@33A (max 180W for both), 12V@15A. The reason
I know the numbers, is I have one too (only I use a R8500, which
doesn't need nearly as much power as the 5900).
On an AMD motherboard, there generally isn't a 2x2 connector for +12V,
so this motherboard draws processor power from +5V. A 2.6 barton
needs 53.7W @ 1.65V, and that is 32.5 amps. Converted from +5V, this
is 32.5*(1.65/5.0)=10.7 amps. With an assumed conversion efficiency of
80%, the current needed rises to 13.4 amps from the +5V supply.
The Nvidia 5900 draws 5V@10A and 12V@2A, under some 3D gaming conditions.
This is purely a guesstimate, based on some numbers from a power supply
estimator website.
The sum of those two numbers, is 23.4A from +5V. Out of 33A available,
this still sounds safe.
Now, consider the combined power limit. Of the 180W combined allowed
on +3.3 and +5.0, 117W is consumed by the +5V. This leaves 63 watts
from 3.3V, or 19 amps. From this, you could be powering DIMMs (maybe
5W a piece), and any PCI bus based chips could be drawing from +3.3V
as well.
On the surface, there should be enough power there, so maybe your
PSU is a little weak, or you have some other loads you haven't mentioned.
Get a copy of Motherboard Monitor (MBM5) from livewiredev.com .
Check the voltages using the MBM5 dashboard, while you do some
stuff. What I would expect you would see, is the +5V a little on
the low side (the most stressed supply), +12V on the high side,
and +3.3V pretty close to normal. Typically, PSUs have a 5% tolerance
on regulation, so if you are seeing larger deviations, like 10% on the
low side on any output, you might consider getting a larger supply.
The other possibility, is the AGP interface just isn't ready to
transfer data at the rate the FX5900 is capable of. You might try
reducing the AGP transfer rate setting, to see if you can get some
stability. You could try disabling fast write, if the motherboard has
such an option in the BIOS. Once you can get the motherboard to "stay up"
for a few minutes, then it is time to try 3Dmark in demo mode (3dmark2001se
if using directx8, 3dmark2003 if directx9, I think). This will do a
good job of making the video card draw current representative
of a gaming situation. Before starting 3dmark, enter the options menu
for MBM5, and enable the "logging to txt file" function. Set it to
record all readings at 10 second intervals. If the computer goes
berserk at some point, and reboots, open the txt file after the
computer reboots, and examine the recorded values near the end of
the file, for anything suspicious.
If you haven't already, you should also run memtest86 on your memory,
to make sure it is solid. Your symptoms don't suggest that memory
is an issue, but error free memory is a good thing to test for
anyway.
HTH,
Paul
