Monitor goes into sleep mode after installing a new graphics card

  ScootyUk 19:14 15 May 2014

Hi PC tech heads,

Here is a testing one for you as I am completely stumped.

First of all, below is the setup of the build I just completed.

Windows 7 Professional 64-bit Intel Core i5 4670K @ 3.40GHz 8.00GB Dual-Channel DDR3 @ 665MHz Phillips 274E5 Monitor ([email protected]) Saphire R9 280X Toxic 3G 5DDR5 1863GB Seagate ST2000DM 001-1CH164 SCSI Disk Device (SATA) 2 Intake fans on a 2 way splitter 2 exhaust fans on a splitter 1 intake fan cpu cooler with x2 fans Cooler Master GX 650W bronze power supply

My pc has been running fine using the built in graphics on the cpu, everything was running ok until I decided to get some thing more powerful. I have just installed a Saphire Toxic R9 280X, it has been running fine and I was impressed by its results.

The problem.

1) My monitor keeps going into sleep mode and says there is nothing detected, it happened a few times at first, now its permanent. I have plugged the HDMI back into the motherboard to use the onboard graphics instead.

Would this be something to do with the psu not being powerful enough, Saphire recommend a 750W power supply or could the gpu be faulty.... I'm totally lost.

All drivers are up to date.

Please help someone, I'm pulling my hair out here.

Many thanks


  rdave13 20:14 15 May 2014

Usually the recommended PSU for cards is the minimum. MechKB 2 should be able to give you better advice if he pops in.

Try reseating the card again and check the power connection/s to it. If all is sound, it's a possibility the card is defunct and you should contact the seller.

  Mr Mistoffelees 20:34 15 May 2014

On the Sapphire website it says a 750W PSU is "required" yet also says the card requires two 8 pin power connections (150W each), ie 300W plus the power supplied by the PCI-E bus, a maximum total of 375W. As you have a decent quality PSU it should be able to cope, although possibly running near maximum output, under heavy load in games, notwithstanding that the graphics card will not be using as much as that 375W maximum. According to a standard R9 280X uses up to 250W, your overclocked card will not use much more so, I think Sapphire are being over cautious.

  alanrwood 20:45 15 May 2014

Have you changed the primary graphics source in the BIOS to the PCIe ??? card

  Menzie 15:50 16 May 2014

Since the problem has now become permanent I would say the card is faulty. Try checking the card is fully seated into the slot as given in the advice above. Also check the BIOS is pointing to the PCIe slot for video output.

I had an issue with my card where my monitor would be in standby until Windows came up. Turns out that my TV which was connected to the DVI slot and the computer made this the primary display. You have a single monitor however so this shouldn't be the case.

  alanrwood 19:02 16 May 2014

Hi MechKB 2

Sorry but the graphics card is not always automatically recognised by the computer's BIOS. I fitted one to a computer a couple of weeks ago and it was not recognised at all until I booted using the onboard graphics and changed the BIOS settings to primary selection as PCIe. OK the M/B was about 3 years old but that is not particularly old

  alanrwood 09:21 17 May 2014


Going away in an hour or so for the weekend so will try and get back sometime next week.

  ScootyUk 09:27 17 May 2014

I've gone the easiest way, they are both under warranty so I'm replacing the psu with a corsair cx750 and the gpu is going back to sapphire for testing.... So much for a new build, it will be resolved....

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