Having problems installing my second GPU, please help me

I am attempting to crossfire 2 7870's; one a MSI and the other a visiontek. The MOBO is a asrock z77 extreme 4 and i have a Corsair CX 750w PSU. windows 7 ultimate

So I installed the second GPU and booted up the system and it immediately went to my UEFI screen. I exited UEFI and windows could not boot. I then decided to try running my system with just the new GPU and everything booted up fine and my drivers were installed. I shut down my PC and put my old GPU into the second PCI-E slot and tried booting again with the same issue.. immediately to UEFI which i exited and then windows would not boot. I tried booting with the crossfire bridge connected and not connected which made no difference. and obviously neither did switch GPU positions.

I am fearful that maybe this could be a defective PCI-E slot issue but dont really know enough about this stuff to say especially since this is my first crossfire attempt. I will say that when in UEFI the MOBO map i pulled up did show 2 devices connected to both PCI-E slots with the same descriptions.

please tell me there is an easy solution that I am just too noob to see, thanks!

anyone?

define "not boot" when you use the gpu in the second pci slot. You get to UEFI, so the GPU *is* working in the second slot. To what degree is a different question.

I assume you are connecting the monitor to the GPU and not the onboard iGPU output correct. Generally with the GPU installed iGPU disables.

Have you confirmed both PCI-E slots are enabled in the bios?

Firstly Id start by removing all gpu's and performing a Clear of the BIOS using the button on the back IO. <- do this with the machine powered off.
alternatively you can use the jumpers on the mobo to perform the same thing. Again, do it with the machine powered off.

Put in your GPU and boot. Load optimized defaults. F10 to save and restart.
Once back in the BIOS, check your iGPU is disabled.
Check that primary display is set to PCI-E.
Confirm system boots.
Shutdown.
Install second GPU with Crossfire bridge.
Boot.

Report back.

Make a 30 second recording/video of it. Upload it on youtube and give us the link.

Use the Crossfire bridge, in your BIOS make sure both GPUs are running @ X8, connect your HDMI/DVI to your top (main GPU).

by not boot i mean once i exit uefi i am stuck with a permanent black screen while a single light on my key board slowly flickers.

i connect to my monitor via a DVI cable that plugs into my top GPU

how do i know for sure if both pci-e slots are enabled? im pretty sure they are because someone suggested i change speed to gen1/2 on another forum

remove all gpu's and perform a clear of the bios using the button on the back IO? i don't know what you mean

load optimized defaults? does this mean ill have to cancel my CPU oc settings?

where do i check iGPU is disabled?

and where do i check primary display is set to PCI-E?

ive run my pc with 1 7870 for a long time with no issues so i dont think any of these settings are a problem and if by remove all GPU's ur talking about the drivers ive tried that too. someone on another forum had me use driver sweeper to clear all drivers and reinstall one by one.

there isn't much to see, when i say windows won't boot i mean it just shows a black screen.

the video will look like instantly loading to UEFI then i would exit it and an infinite black screen would come next.

Insaine_metalist: why would i want my GPU's running at x8? they can both run at x16. i am connected to the top GPU via DVI

Use the Crossfire bridge, in your BIOS make sure both GPUs are running @ X8, connect your HDMI/DVI to your top (main GPU).

When you're using two GPUs on a Z77 board they will run @ X8 max. Single GPU will run @ X16.

how do i change that setting?

and what are the disadvantages to running at 8/8 as opposed to 16/16?

Opps replied to the wrong person with my last deleted post.

8/8 hardly makes a difference between that and 16/16 for just two cards. Its not worth the upgrade if you are cross-firing two cards. The only modern boards that can do it is 16/16 are lga 2011 or lga 2011-3. Its not worth it if you are only x-firing two cards.

ok, thanks for that.

the only speeds i can change to are gen1/2/3 for my pci-e slots as far as i know

if someone can help me resolve this tonight asap that would be great i have work at 6am and this has been a 2 week long headache. really looking forward to putting this behind me.

Could this be because the clock speeds of your GPU are different? Its been awhile since I played around with x-fire. You might have to set the clock speeds identical.

Maybe do a bios update for the heck of it and see what happens.

how do i do a bios update? when in eufi under advanced i tried to flash it with the top option and it said something along the lines of no device. then i tried the internet flash option below it and it said it could not establish a connection to the internet, but clearly by net works in windows.

how would i set the clock speeds identical? they are different, but as far as i knew it would just run to the lowest GPU's capabilities.

I am not very good at this stuff so to all who try to help please try to make it as idiot proof as possible, i need more guidance.

@TheProdigy619: frustration is reaching epic proportions. i really dont know how much more patience i have for this process.

someone please have the kindness to hold me by the hand and guide me through this ><

someone on another forum suggested flashing one of the GPU's BIOS to the others and said there were plenty of tutorial videos out there. anyone else think this is a good idea at this point?

if you have tried using one card in 2nd slot and neither work then its the pci-e slot. And its not disabled it might just be bad

both cards work in the second pci-e slot.

dark susperia what does this mean: Firstly Id start by removing all gpu's and performing a Clear of the BIOS using the button on the back IO. <- do this with the machine powered off.

Here is a thought what power supply are you using?

ugh that is listed in the first line of the first post ><

corsair cx 750w

I think, Gen 3 is what you need. Just read at the bottom it will explain everything (Gen 1, 2 &3).

Do the gpu's work separately? like when you put them in the first pci-e slot do they both work?

When that is ok check your motherboard if you're using the right slot for the gpu , you should use one that has pci-e or x16.

Your motherboard has 3 pci-e x16 slots, so they can't be all broken, those pci-e slots work seperately as well, you can test them with one card.

Make sure you use a crossfire bridge, make sure both gpu's are correctly powered by your psu (cables need to be connected). Try a different crossfire bridge.

Is there a setting in your motherboard that enables/disables the pci-e slots

How old is your psu? Do you have any overlclocked stuff in your pc?

Make sure your vga cable/hdmi/dvi is in the first vga card.

Disable any onboard vga video, can be on the motherboard or one in your cpu (what cpu do you have?)

If you can get the Bios screen up with both GPU's inserted a last resort could be reinstall Windows with both GPU's already inserted, then update the drivers once everything else on windows is set up.

It seems like everything is fine, its windows screwing up and cant load the drivers properly, might be worth a shot if all else fails.

I'm due to crossfire my 7850 very soon.

Also one more thing. Double check that your mobo actually supports Crossfire.

On the back of your computer, where you plug in your USB cables etc, there is a white button. CLR CMOS...

With your machine off, hold the button in for a couple seconds to clear your BIOS.
It will default your machine back to "out of the box" settings. Yes you will lose your overclock.
Once in the BIOS, go to save and exit and choose "Load optimized defaults".
Press F10 and save and exit.
Power off.

Put in both GPU's WITH the crossfire bridge.
power on.

Wont necessarily need to reinstall to test that. Just uninstall the drivers entirely. Drop in the second card and see if it boots.

OP, follow this to uninstall completely if you wish to try that route.

How to remove amd drivers

ok, gunna try this now. can anyone say anything about flashing the BIOS on one of my GPU's to match my other? this was recommended to me by sum1 on another forum who had a very similar issue.

this didnt work either

i did load uefi defaults, didnt see any optimized defaults

I know, I did say it as an all else fails idea, might as well if all other options have been exhausted.

Do you know for a certainty that the Crossfire bridge works?

no, just recieved it from ebay a couple days ago and have never used it b4.

ill see if i can get another to test with.

im feeling like i've tried everything so if that doesnt work im returning the card..

baffled by how unbelievably hard this is. another wasted effort.... went to fry's and got another crossfire bridge and nothing changed... i guess im just going to have to send this card back and try to get the same exact card i already have.

what the f could be wrong? i am so frustrated.

EDIT: just wanted to update you guys, i did a fresh install of windows and ALL of my devices drivers and now crossfire works. i guess driver sweeper didnt fully remove old drivers >< i bet that guide that was posted on removing drivers in an earlier post would have done the trick too.

thanks for all the help.

Called It :D

I got my crossfire set up (x 2 7850) working today, had trouble at first with the Catalyst control centre saying the bridge was not connected properly.

After research figured out your not meant to push each cable in all the way, anyway glad your up and running post here what kind of performance you get.

It should be similar to mine as both my 7850 are over clocked and match 7870 stock performance.