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Graphics card not detected - PSU problem?

Discussion in 'Hardware' started by Astropuffin, Apr 17, 2011.

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  1. Astropuffin

    Astropuffin Thread Starter

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    Tech Support Guy System Info Utility version 1.0.0.1
    OS Version: Microsoft Windows 7 Professional , 32 bit
    Processor: Pentium(R) Dual-Core CPU E6500 @ 2.93GHz, x64 Family 6 Model 23 Stepping 10
    Processor Count: 2
    RAM: 3549 Mb
    Graphics Card: Intel(R) G41 Express Chipset, 1550 Mb
    Hard Drives: C: Total - 305142 MB, Free - 227675 MB;
    Motherboard: ASUSTeK Computer INC., P5G41-M LE, Rev X.0x, MF70A6G04802126
    Antivirus: AVG Anti-Virus Free Edition 2011, Updated and Enabled

    Hi,

    I'm pretty new to opening computers and adjusting their hardware, but recently tried to install a graphics card into my desktop computer. The only graphics card at the time was the onboard one. I tried to install a Sapphire Radeon HD5670 PCI-E card. I disabled (rather than uninstalled) the onboard graphics card, doing this on the device manager. I put the new card in, it seemed to click into place and I'm sure it was in all the way. I plugged the monitor into the card's VGA port, turned it on and - no image appeared on the screen.

    I plugged the monitor back into the onboard graphics card port, and an image appeared. When Windows 7 loaded, it did not detect any new hardware. I looked on the internet, and some people seemed to suggest that I should go into BIOS and somehow tell the computer to look in the PCI-E slot for a graphics card there. I couldn't find any settings that allowed me to do that - making me wonder if other people have the same BIOS options that I do.

    Opening up the computer again, the fans on the card (it's a half-height card for a slim desktop case, hence fans plural) seemed warm, which I thought must mean that it was taking power. But eventually I took a look at the PSU, and say that it said Total Output Power: 250W. The card, however, had minimum requirements of 400W. Ah. (I then removed the card again, as I understood that taking more power than the PSU could provide would damage the components.)


    Okay, so these are my questions, which I would be very grateful if anyone could answer:
    • Does it sound like having too small a power source is my only problem? Would the result of too low wattage normally be that the rest of the computer would start up as normal, but that the new graphics card would not work and not be detected?
    • If I were to get a new PSU - it looks as if the case is designed to fit a PSU of a specific shape. Would a higher wattage PSU necessarily be physically bigger? Or should this not be a problem?
    • If I were to replace a 250W PSU with, say, a 500W PSU then, assuming equal levels of efficiency, would the 500W PSU draw twice as much power from the mains for all of the time that the computer was on? Or would it just draw as much power as it needed for whatever it was doing at the time?
    • If the graphics card were plugged in, would it be drawing its full ration from the PSU all of the time, or would it only go up significantly when it was being used for demanding activities, such as playing games?
    If it is just a matter of getting a new PSU, I think I'll do that, but if it just leads to me having to get loads of other things upgraded as well, I might have to give up, as I'm only expecting to use the PC for a couple of games anyway.

    Thanks very much if anyone can help!
     
  2. Frank4d

    Frank4d Trusted Advisor

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    A 500W power supply probably will be physically larger; whether it will fit depends on the design of your case. An ATX12V power supply up to 450 watts measures approximately 150 mm wide X 140 mm deep X 86 mm high. Some higher wattage power supplies may be larger, usually the depth is longer.

    Regarding you questions about power, it will draw only the amount of power that is needed for what it is doing at the time
     
  3. Astropuffin

    Astropuffin Thread Starter

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    Messages:
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    Thanks for the advice, I'll try and measure the PSU cavity and see what I've got to play with.

    Does anyone know if low power would cause a graphics card not to be detected? I'd have thought that low power would stop the whole computer from working. Why might a computer not detect a graphics card?

    It just seems to me that there must be something else that's also stopping it working.
     
  4. Frank4d

    Frank4d Trusted Advisor

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    According to the manual, in the BIOS setup utility under Advanced > Chipset > Initiate Graphics Adapter, you should see options for IGD, PCI/IGD, PEG/PCI, PCI/PEG and PEG/IGD.

    I would think you want "PEG/PCI" which is supposed to be the default setting. It tells the BIOS to use a PCI-E graphics card, and if not found then use a PCI card. If neither are found, it will use the integrated graphics.

    If you already have that then something else is wrong; and I agree that if it was overloading the PSU the computer would not work.
     
  5. Astropuffin

    Astropuffin Thread Starter

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    That's amazing, I think that's the one piece of information I'd been looking for and hadn't been able to find. When I look at Chipset, I instead get the options of "Northbridge" and "Southbridge", with big capital lettered warnings that meddling with these options could cause a complete system malfunction, so I'd been afraid of checking further. I just tried selecting Northbridge and the options you mentioned were there. I won't put the graphics card back in yet, I'll look into power supplies first.

    Again, you've been a great help. Cheers!
     
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