Sufficient power for new setup?

Drawis

Honorable
Feb 7, 2013
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10,510
Hi there.
I have a new Gigabyte motherboard running an i7 3.4 GHz processor.

The system boots up and works fine using the onboard graphics from the motherboard. The i7 is presumably drawing more power than the previous Core2 Duo chip on the previous motherboard?

However when I attach a brand new Gigabyte 7870 card into the PCI-E slot and connect up to it the two 6 pin power connectors (as I used to with my old 8800Gtx card on my old mobo) the computer whirrs when powered up but I just get a completely black screen on my monitor. No beeps, the computer just sits there.
It doesn't sound as if the operating system is booting at all.

I'm running ubuntu 12.04 and haven't got as far as updating drivers yet because, obviously, I haven't booted it up with the card in.

Is this down to insufficient power or a defective power supply?
My PSU is a HEC-550td-pte which came with a Mesh PC. It is 550 watts.
It has one 6 pin connector coming straight from the supply and the second one attaches to two four pin connectors in the usual way.


Help!
 
It might be the power supply. I would rather have a 650 Watt in that setup. But before you break out the checkbook, try installing the drivers before you install the card.
 
A HD7870 should run fine on a 550W PSU, so yours is probably not capable of outputting 550W; certainly not cleanly. HEC does not enjoy a particularly good reputation for PSUs.
Why would you want a HD7870 on a Linux box?
 
Why not? Steam etc. but I'm probably going to dual boot with windows7.

Would the lack of power result in the symptoms I'm seeing?

Not sure how to install drivers. Ubuntu ordinarily finds them once booted.
 
Also, when I connect the two 4 pin adapters to the 6 pin that goes in to the card, does it matter which 4 pin adapters I choose? There are 4 spare and they all look alike to me??
 
Regardless of what is on its label (most likely a lie), since the PSU does not have two PCIe power cables, it probably lacks +12V rail amperage to properly power your card.
You can try attaching the adapter to molex plugs on two different cables, BUT, if the PSU can't hack the load, it may be driven out of spec, which could damage your equipment. You are proceeding at your own risk.
 


When you boot into the BIOS, does it have a section on the selection of the Graphics card instead of onboard graphics. Some automatically switch others require you to select in the BIOS. Something like PCI vs onboard?

I would expect though based on your description it is that your power supply can't handle the computer.
 
I'll try getting into the BIOS (is it the DEL key?) but I'm not getting even a flicker of life on the screen so it's a bit chicken and egg- no graphics so can't adjust settings...
 
Right, the problem continues.

I have fitted a brand new PSU.

I can still fire up the computer using the onboard graphics.

I have checked the Bios settings (Gigabyte board) and have set the graphics option to 'PEG' and onboard graphics as disabled.

However when I switch on the monitor isn't recognising any video signal at all.

I don't think the graphics card is faulty. The fans on it work and it is a replacement for the last one which I returned (probably, looking back, that one was OK- I find it hard to believe that two consecutive cards are both faulty)

Do I need to meddle further with the BIOS settings?

What else is there?

 


That is about all there is. Sounds like a bad card.