New graphics card - no signal

[tommi712]

Hi, I have bought new graphics card - AMD Gigabyte HD 7870. My old card worked fine, I have unninstalled all drivers and then i shut off pc. I put the new 7870, power supply and monitor cable plugged in, turned on the pc and nothing. Monitor says no signal, vents on 7870 are working, but just black screen.
I have already reseted BIOS by putting of the CMOS battery, in BIOS selected the main VGA to PCI-e and now i dont know what to do. Sorry for my eng.

 

[Groomer]

Is your monitor connected to the graphics card, and not to the motherboard?

 

[tommi712]

Yes it is

 

[tommi712]

I dont have onboard graphic card. My old one works just fine. I was thinking about reinstalling the windows, but i dont think it will change anything. I think there is some problem with mobo but i dont know what is wrong.

 

[Groomer]

What card did you have before?

 

[tommi712]

I had Sapphire HD 5850 Toxic

 

[Chox]

This may seem silly but it happened to me recently when installing a 7970 - have you left the rubber cap on the bit where you plug the CrossFireX bridge in?

I did and i had the same problem you described until I removed it.

Update: My card was also a gigabyte

 

[Carl Angelo De Leon]

tell the bios to boot pciex16 lane

 

[tommi712]

Yes i already removed the rubber cap

 

[tommi712]

Carl Angelo: my mobo is Intel P55KG and in BIOS i can only select in Advanced > Video Configuration - Primary Video Adaptor > Auto / Ext PCIe Graphics (PEG) / Ext PCI Graphics

 

[Carl Angelo De Leon]

Carl Angelo: my mobo is Intel P55KG and in BIOS i can only select in Advanced > Video Configuration - Primary Video Adaptor > Auto / Ext PCIe Graphics (PEG) / Ext PCI Graphics

select the pcie graphics

 

[tommi712]

i already have

 

[Chox]

both 6-pin PSU cables are plugged in to the card and it's seated in the PCIe slot correctly?

 

[Carl Angelo De Leon]

how could you go to bios if you see nothing?

 

[tommi712]

seated correctly, bot 6pins plugged in, Carl: im changing between my old card and my new one

 

[Chox]

What PSU do you have?

 

[Carl Angelo De Leon]

what is the brand of your psu, wattage and amperage in12V rail?

 

[tommi712]

http://www.newegg.com/Product/Product.aspx?Item=N82E16817104046

 

[Carl Angelo De Leon]

i knew it, it was the PSU. you should change your PSU, get atleast 600w with 2, i repeat, 2 6-pin connectors. dont try to open your PC again unless you change your psu, you might burn the card because of the lack of power

 

[tommi712]

Thats good news, I will do that, thank you for helping me.

 

[Carl Angelo De Leon]

get a corsair, antec or seasonic PSU with the above specs as mentioned and you're good to go

 

[tommi712]

And one more question. Why the old graphics worked and the 7870 is not working? Isn't the power consumption with 7870 better and its more effective than 5850? Or why is that?

 

[Carl Angelo De Leon]

that's because the HD 7870 needs 2 6-pin connector but your PSU has only one, also, let alone the 400w PSU. the HD7870 is considered as medium-high range graphic card. you have a very capable GPU, you should pair it with a good PSU. this is the principle, you can cheap out a GPU but never do that with a PSU because if the PSU fails to give the required power, it will take down all the other components, even the whole motherboard too

 

[Chox]

Try a Corsair CX600 or TX 650, they're both great.

 

[tommi712]

I borrowed from my friend Evolve 500W (very cheap PSU) and still not working... how is it possible, the card has so big consumption or what, i still dont get it... of course i will buy some better PSU, i am just asking and trying. I didnt think it is so big step from HD5850.