I can not make 2 differnt AMD cards work in one machine

[muziqaz]

Not sure about the PCIe lanes on a C602 based Mobo … https://ark.intel.com/content/www/us/en ... ipset.html

CPU itself has 40 lanes

and its not 12 core CPU its 6 core 12 thread CPU.
Its server version of Sandy bridge E x79 s2011. It should be fine with multi GPUs

[Neil-B]

Not sure about the PCIe lanes on a C602 based Mobo … https://ark.intel.com/content/www/us/en ... ipset.html

CPU itself has 40 lanes

and its not 12 core CPU its 6 core 12 thread CPU.
Its server version of Sandy bridge E x79 s2011. It should be fine with multi GPUs

You seem to have more info than the OP has posted here - so I'll defer to your better knowledge … I was working on the information posted which indicated a c602 chipset motherboard which as per Intel only supports:

Expansion Options
PCI Support
Yes

PCI Express Revision
2.0

PCI Express Configurations ‡
2x4, 4x2, 8x1

Max # of PCI Express Lanes
8

… but hey, what do I know, I'm a pure CPU folder and the arcane'ness that is PCI is not something I dabble in particularly much

Ah OK, further reading leads me to understand that the PCIe Slots come straight from the CPU not the chipset?? … Forgive my ignorance.

[muziqaz]

Not sure about the PCIe lanes on a C602 based Mobo … https://ark.intel.com/content/www/us/en ... ipset.html

CPU itself has 40 lanes

and its not 12 core CPU its 6 core 12 thread CPU.
Its server version of Sandy bridge E x79 s2011. It should be fine with multi GPUs

You seem to have more info than the OP has posted here - so I'll defer to your better knowledge … I was working on the information posted which indicated a c602 chipset motherboard which as per Intel only supports:

Expansion Options
PCI Support
Yes

PCI Express Revision
2.0

PCI Express Configurations ‡
2x4, 4x2, 8x1

Max # of PCI Express Lanes
8

… but hey, what do I know, I'm a pure CPU folder and the arcane'ness that is PCI is not something I dabble in particularly much

Ah OK, further reading leads me to understand that the PCIe Slots come straight from the CPU not the chipset?? … Forgive my ignorance.

Chipset has 8 lanes, most of them reserved for chipset<-->chipset interconnects.
CPUs come with their own pcie controllers and are main supply for that connectivity.
That's why in past few years intel got ridiculed by AMD about their desktop cpu PCI-e lane number.
Today's CPUs work same way
Also, OP mentioned 12 cores, which didn't exist at that time (Sandy Bridge topped out at 6 cores on Patsburg(c602) chipset), so I assumed it was 12 thread one

[Skajaquada]

I have no driver issues in my new build using a 5700xt together with a 5500xt and/or a rx480 and rx580.
My power supply has 700 watt and there are also no problems, i think it depends on your MoBo PCIe config.
I upgraded to a X570 and have no other board left to test another build.

[paulmd199]

PSU seems adequate. We haven't got it to POST, so drivers don't come into play just yet. That leaves BIOS updates and settings.

Edit: it can still be the PSU, but that would imply a partial failure of the unit itself.

[muziqaz]

I vote with BIOS settings/bios switch/bios version

[paulmd199]

PS Unit is a Corsair HX 850, so there should be ample power.

There is one last thing to check w/r/t the PSU. Your model has a feature that allows each individual rail to be limited to 40A. Your two cards together can draw up to 34A. While this seems adequate, if there is something else sharing the rail, you can still run into issues.

If the manual is correct, you can toggle this limiting feature off by setting the switch to the "single" position.

+12V rail selection switch
The HX Series power supplies are equipped with a +12V Rail Selection Switch that gives you the choice of single or multiple +12v rails. In the “SINGLE” position, the full output of the power supply’s +12V rail is available to any and all connectors, while in the “MULTIPLE” position, each individual connector has Over-Current Protection so no more than 40A of current can be delivered on any given cable.

https://www.corsair.com/corsairmedia/sy ... Manual.pdf

[ChrisD5710]

@muziqaz

It is indeed a 12 core Xeon CPU (12 cores / 24 threads )

It does POST with 2 cards installed, it even starts loading windows, but as I cannot see anything, I just have to pull the switch. When I then remove one of the 2 cards and get my video back, I can see that it had tried to load windows.

I have checked the BIOS, and I can not seem to locate a feature that selects one video card over another, so that was a no go.

Again, thanks for Your replies

ChrisD5710

[muziqaz]

@muziqaz

It is indeed a 12 core Xeon CPU (12 cores / 24 threads )

It does POST with 2 cards installed, it even starts loading windows, but as I cannot see anything, I just have to pull the switch. When I then remove one of the 2 cards and get my video back, I can see that it had tried to load windows.

I have checked the BIOS, and I can not seem to locate a feature that selects one video card over another, so that was a no go.

Again, thanks for Your replies

ChrisD5710

Are you from alternative reality? Intel with socket which supports multiple generations of CPUs? That can't be right?
Anyways, first rule when asking hardware question on any internet forum: provide all the information of your system, and I mean ALL, even engineer's name who designed specific section of your CPU, or Intel fab cleaners name, who swept that night when your CPU was being cooked from sand. That way we save a lot of time from guessing what you are running and why you have issues

[Neil-B]

Really off beat question … Does the Mobo have onboard graphics as well? … if so under certain situations it may default back to using that so you might want to have a monitor cabled in off that just to check.

[paulmd199]

It woulda been nice to know you'd gotten into Windows.

It's probably only one thing at this point. BIOS setting that enables the onboard video. It's probably set to AUTO. Try forcing it to be always on, then plug your monitor into the onboard port. Let's get this thing making a picture at least and then see what we can do about your cards.

[ChrisD5710]

@muziqas

Sorry, I seem to have made a blunder, South Bridge is a C206, not 602. I do not know how I got this all wrong. I am very sorry for that. Please forgive me.

Anyone still talking to me? If so, Here is all the info You need:

http://lundbykrat.com/MB/XEON-FM.html

Once again, sorry for the "typo".

ChrisD5710

[bruce]

Please confirm that the latest drivers sill support the older GPU. I've had troubles like that before when new drivers drop support for old GPUs and older drivers don't support the newer hardware.

[Neil-B]

Hey, you have an interesting problem that isn't a server issue - of course people will still be talking to you ... Any we have all made mistakes with part numbers/codes/references at some point !!

[muziqaz]

@bruce, latest driver still supports old GPU.

C206/602 mistake makes no difference still same platform, and very rare unreleased CPU you have there.
Things to do first:
Update BIOS
Check and fiddle around with PCI-e lanes in BIOS, if not sure, take photos of related sections of BIOS and post them here, we might be able to advice on what to set and where.
Also, do not discount above suggestions about iGPU.

Also, today I had very interesting experience with dual GPU system.
When restarted or cold booted it what seemed to not be able to enter UEFI(BIOS). It would just go straight to windows without any POST period. And when I would smash Del/F2 keys to go to BIOS, computer would seem to get stuck without any errors, and no signal to display. For half an hour I was resetting the PC, even took out battery to reset BIOS, which I managed to do, still could not enter BIOS.
Display port cable was connected to primary 5700XT card as always. Then I read somewhere that sometimes POST and BIOS show up to different GPU outlet port, since both of my GPUs have 3 DP and 1 HDMI outlet each, I started going through all of them, and what do you know, BIOS shows up when I have my Display Port cable plugged in into second DP port of secondary card (Vega64).
So yeah, food for thought.

Back in the days of Radeon HD5780s, I remember I could only get signal to monitor from secondary card for several generations. Try it yourself, you never know