Sli Problem found why...but not how to fix

[Shadow_Storm56]

So if i remember correctly that for sli to work the gpu needs to run at atleas x8 native. My board is able to run at x16 or x8/x8 it is an asus maximus VIII extreme. It will only run at x8/x4...... Force Gen 3...nothing... literally nothing will make this work. Anyone have ideas? 

[Simon771]

What's your CPU?

Any other devices pluged in PCI lanes?

M.2 ssd?

sata express?

[Emoji]

 

If you have other devices plugged into your PCI lanes it might be taking that power rather than the GPU.

Also, just to make sure just check the BIOS settings just to ensure the PCI lanes are running at their intended speeds.

 

[dragoon20005]

check which slots are for the SLi x8 x8 mode to work

 

not all of the slots are for SLi

 

update the BIOS and see if it helps

[Shadow_Storm56]

One slot says x4 one x8. Optimal is slot 1 and 3. If I do that it assume no graphics cards are installed. Bios is up to date. Board has already been Rmaed with no change in results.... all other components tested to work fine. Only 2 things left I can replace or check . Case and psu 

[Simon771]

2 hours ago, Shadow_Storm56 said:

One slot says x4 one x8. Optimal is slot 1 and 3. If I do that it assume no graphics cards are installed. Bios is up to date. Board has already been Rmaed with no change in results.... all other components tested to work fine. Only 2 things left I can replace or check . Case and psu 

Case and PSU have nothing to do with that.

I suspect that your CPU can handle 16 lanes and you have some other PCI slot taken. That would force one GPU to scale down on x4.

Something is stealing your PCI lanes. The problem is either with motherboard/chipset or CPU.

[Shadow_Storm56]

Case was kinda a joke aha. No other pci is in use though..

[SLAYR]

6 hours ago, Shadow_Storm56 said:

One slot says x4 one x8. Optimal is slot 1 and 3. If I do that it assume no graphics cards are installed. Bios is up to date. Board has already been Rmaed with no change in results.... all other components tested to work fine. Only 2 things left I can replace or check . Case and psu 

 

You need to put the cards in the correct slots. 

 

Look in your manual and it will tell you what slots the gpus need to go in for SLI support. You board supports one x16, or x8/x8/x4 so you are using the x4 slot instead of the x8 slot.

[Shadow_Storm56]

Once again there in the right slotS to work. The recommended slots are 1 and 3 but a my sli bridge is too short for that and b my bios says I have no graphics cards when I used thoes two slots.

[NumLock21]

Your cpu has lanes missing.

[Shadow_Storm56]

Uhhh why ???

[airdeano]

top x16 slot is x16 (PCIE_x16/x8_1)

second x16 slot is x4 when top slot is ocupied

third x16 slot is x8  (PCIE_x16/x8_3)

 

so you'll install GPU in top x16 slot and the second GPU in the third x16 slot for x8/x8 performance.

[Shadow_Storm56]

Yea see when I do that it does not detect either gpu anymore....or just 1 

 

Idk what would make lanes go away. I even used to have a wifi card in there too and it all worked fine. But then suddenly no these issues appeared. 

[straight_stewie]

10 hours ago, Shadow_Storm56 said:

Once again there in the right slotS to work. The recommended slots are 1 and 3 but a my sli bridge is too short for that and b my bios says I have no graphics cards when I used thoes two slots.

Your SLI bridge is too short to put your cards in slots 1 and 3? So how are you having your cards in slot 1 and 3 with the SLI bridge attached? That's a pretty major problem to solve as well.

What are your exact full system specs? This means, all components in your system.

[Shadow_Storm56]

Oh no my like high quality sli bridge is or i guess flashy one is too short. I have one that will go that far. So when it's in slot 1 and 3 the boards like you have no graphics cards... I even have given in and taken it to a tech and he's stumped as well. 

 

Oh god....

6700k

Maximus viii extreme

Gtx 970 x 2

850w psu Thermaltake 

8 hard drives 1 usb, 3 mech, 4 solid, water cooled setup...idk what else ya wanna know.

 

[straight_stewie]

13 minutes ago, Shadow_Storm56 said:

Oh god....

6700k

Maximus viii extreme

Gtx 970 x 2

850w psu Thermaltake 

8 hard drives 1 usb, 3 mech, 4 solid, water cooled setup...idk what else ya wanna know.

Is this real? That's alot of hard drives.

But I digress, are you in a position to take a single graphics card, one that you are sure works properly, and insert it into slot 1 and check it's speed, then remove it and reinsert it into slot 3 and check it's speed?

[Shadow_Storm56]

I do raid..... and yea I did that already.... the slots run at 8x :(. 

 

It's really annoying me.

 

Really making my miss my 3930k 

[straight_stewie]

25 minutes ago, Shadow_Storm56 said:

I do raid..... and yea I did that already.... the slots run at 8x :(. 

Well, I guess you won't be having any problems with ants then. 

Have you tested both cards in both slots, one at a time? (I mean, did you do the test once, or twice, once with each card)?

[Shadow_Storm56]

I have literally tested every possible configuration aha. Crap it's not the cpu either I remember now I borrowed the cpu In my mom's pc to test that. I have done the test probably 15 times with each card. Plus a bunch more in other configurations... it dosent even show 8x/8x as aN option in my bios anymore. I think my computer has become sentient and hates me. 

 

And ant joke is so old btw 

 

I really just wanna sell my board and cpu/waterblock... buy a sabertooth x79 off ebay and use my 3930k.until I physically broke the board that system worked great. Then I get x16/x16. Because literally theres is no reason why my system will not work but it dosent work. 

[airdeano]

9 hours ago, Shadow_Storm56 said:

Yea see when I do that it does not detect either gpu anymore....or just 1 

 

Idk what would make lanes go away. I even used to have a wifi card in there too and it all worked fine. But then suddenly no these issues appeared. 

then the motherboard is damaged (pin or trace damage), power to the PCIe slot has failed or power to the GPU has failed.

does another device in the slot 3 function?

[Shadow_Storm56]

i already had the motherboard replaced already. power has no issue either and nothing in it to take slot 3 function. The only thing left is to assume asus sent me a broken board when i sent them my board with issues i got another one with issues. The report said that the board i got back had been in because it had display issues but debug was all fine. 

[straight_stewie]

This is a tough problem. I'm not sure of anything that could cause this that we haven't already tested for. The chance of getting two defective new boards in a row is slim to none.

Wait a minute, were both of these boards brand new, unopened box?

[Shadow_Storm56]

first was new second was an RMA return from asus 

[straight_stewie]

Have you tried contacting Asus support, and carrying it through until you get to a "case management" type situation? I'm sure they would be very interested in this issue. 

[Shadow_Storm56]

No when i contacted they were like lets RMA again and i was like oh no not again...