How can you tell if your power supply isn't powerful enough for your video card?

Archaea

Archaea

[H]F Junkie
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How does this problem reveal itself?

Does your PC lock up? Does it "hitch" in games like hiccup? Does it blue screen? Does it make artifacts? I'm just curious what the general manifestation of a power problem is if you've got more video card than your PSU can handle.
 
For my system, 460W powering a 8800 Ultra with 3 harddrives, the computer refused to boot up.
 
pazhman said:
It won't boot or if it does boot it might crash occasionally.
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It won't boot, after BIOS page it just went blank if I remembered correctly. Anyway, I replaced with Corsair 620W then everything went fine.
 
Usually you'll get extreme choppiness in games or just hard locks in games.
 
350W generic piece of garbage and a x1950pro:
Display was effectively "grey"scale - except in shades of yellow.
But everything seemed to work fine, at least for the three minutes I let it run, though I'm sure trying to run a game would have killed it in short order.
 
Almost anything can happen.
It depends what chokes first from lack of power.
The graphics card isnt the only thing that can fail.
 
For me it was random reboots during gaming. drove me nuts trying to figure out the cause too.
 
Most new cards actually know when they're not getting enough power, and will power down and give you an error message. The PSU might trip overload protection if you're drawing above the maximum it can deliver (often way less than rated).
 
pfunkman said:
For me it was random reboots during gaming. drove me nuts trying to figure out the cause too.
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Yeah, this is typically what I've seen happen. You won't see any 'nice' effects like a cpu throttling back or framerates dropping or hitching, you'll be kicked in the face with a BSOD if you're very lucky or, much more likely, just a flat out 'insta-reboot'.
 
spine said:
Yeah, this is typically what I've seen happen. You won't see any 'nice' effects like a cpu throttling back or framerates dropping or hitching, you'll be kicked in the face with a BSOD if you're very lucky or, much more likely, just a flat out 'insta-reboot'.
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You know this reminds me of my old computer that had this problem as well.. I NEVER figured it was the power supply lol. It was so sporadic that I never thought to blame the PSU.
 
Eastcoasthandle said:
believe it or not your CPU, etc will be hotter then normal. But you won't know that off the bat.
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Why would a weak psu make your components run hotter? Maybe a psu with a weak fan would indirectly result in that, but not just one with weak power output?
 
spine said:
Why would a weak psu make your components run hotter? Maybe a psu with a weak fan would indirectly result in that, but not just one with weak power output?
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PSUs generally get noisier the nearer they get to their max output.
This noise doesnt just affect the stability of components, it is also dissipated by the components and makes them hotter.

Because the PSU's voltages start dropping once they are on the limit of current output, there can be a subsequent drop in power but the noise can easily make up for this when the PSU is pushed too hard.
 
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