I just bought a mobo that was untested. If it works it is a great deal so I took a chance. Currently my cheap 450W power supply provides just about 3.3V/5V/12V to the old motherboard but to the new higher-powered motherboard it is about 96% of rated voltage according to the onboard sensors. My multimeter is missing so I can’t test the voltage directly. The mew mobo works fine until Windows starts (the window panes start showing) and then it reboots which tell me it is an undervoltage problem.
- Will different motherboards draw different voltage? Does it make sense that a mobo that draws more power will show an undervoltage on a 450W PS?
- Should getting a new power supply fix the problem?
- Does it sound like a defective mobo?
Do you have another system that’s known to be working to test with? Either plug that system’s psu into your new mb, or plug your psu into the other system. That’s the quickest way to figure it out.
96% of rated voltage is a little concerning but acceptable, assuming that’s accurate and it stays that way under load.
What cpu and gpu are you running with that 450w, and is it a generic crappy one?
Maybe the new motherboard is drawing more current. If it wants more than the power supply can supply, then you’ll see a voltage droop. It might be fine until all the peripherals are up and running at full speed, and then droop. This would result in an undervoltage situation after boot.
If you did have your multi-meter, you might be able to see it start at 5V, and then drop down shortly before the reboot.
-D/a
look at the specifications for the motherboard.
many recent motherboards and peripherals need 500W or better.
Check the capacitors. They will be slightly domed if they are bad. This is a typical failure in mother boards.
I agree that it’s plausible a different motherboard could draw more current, causing a voltage drop. That could potentially be fixed by a new power supply.
However, it’s also quite possible this is a defective motherboard.
Can you try running the MB with fewer things that draw power and see if that changes things?
If not, try borrowing a different power supply and see if that helps.
Finally, are you sure it’s a power issue, not a bad driver or corrupted windows install? Will it boot from a windows install/recovery CD or a bootable Linux CD?