PCIe sharing IRQ's??? - I'm guessing?

[apim]

I have an Asus P8B75-V motherboard. My GPU is using the PCIe x16 3.0 slot. I installed a 3ware 9650se in the PCIx x16 2.0 slot and it didn't work. Contacted Asus and they told me that only a graphics card would work in that 2.0 slot. Apparently I can only use the two slots for the same purpose. I had never heard of this before and tried to find some information on google about it, but haven't had any luck. Is this a case of the two slots sharing the same IRQ or is this something entirely different? I would love an explanation on this if anybody can explain or post a link to help me understand.

Can somebody please explain to me how I can purchase a motherboard and determine before-hand, in writing, whether it'll support a GPU on one x16 slot and a raid controller on a second x4/x8/x16 slot? In other words, what feature or specification can I look for on the motherboard that'll tell me that it will handle my GPU and raid controller? Thx.

 

[defaultluser]

That just sounds like bullshit to me. If an x16 wide slot is speced for a 75w video card, it can certainly handle a lower powered raid card. This just sounds like support assholes trying to get you off the phone.

I've never had any trouble fitting smaller PCIe cards into larger slots. Are you SURE you lined up the contacts correctly?

Can you try running your video card in that secondary x16 slot (x4 slot)? It could just be a bad slot, and then there;'s nothing you can do, since it's probably outside warranty period.

Or if you can't get that working,m try turning on onboard video and putting the raid card in the pcie 3.0 x16 .slot.

 

[cyclone3d]

I'm guessing that is didn't even detect the RAID card, correct?

Looking at the manaul for your board, it says this about the PCIe x4 slot:
"1 x PCI Express 2.0 x16 slot [black] (at x4 mode, compatible with PCIe
x1 and x4 devices)"

It doesn't say anything about it only working with video cards.

Asus telling you that it will only work with video cards either means that the person you talked to doesn't know what they are talking about or that they grossly misrepresented what the board actually supports.

Looking further into the manual, have you tried turning on Option ROM Messages [Force BIOS] in the Boot menu?

And what about PCI ROM Priority? Setting it to Legacy might make it work.

You also have a UEFI/Legacy Boot option. Maybe changing it to "both" might help.

Could be that the 3ware card will not work with a UEFI bios. (Upon further looking, it seems that that old 3ware card may not play nice with UEFI)

Does the 3ware card have the latest firmware on it?

Do you have the latest BIOS for your motherboard installed?

 

[apim]

I've never had any trouble fitting smaller PCIe cards into larger slots. Are you SURE you lined up the contacts correctly?

The card fits in the slot just fine. My issue is that the card doesn't operate properly once in the slot. The BIOS displays the card 50% of the time upon booting. Avagotech (3ware) support told me that the card should post in bios 100% of the time during bootup. Avagotech was the one that originally told me that some mobo's don't support GPU + Raid Controller in both slots at the same time and that I had to contact ASUS to confirm. ASUS then confirmed and said I could run GPU's in both slots or Raid Controller's in both slots, but not 1 of each at the same time. Additionally, when I was in Windows 7 64-bit OS, the system would hang for 30+ seconds every 2-3 minutes. ASUS said this was likely because the mobo would switch to the RAID Controller and ignore the GPU as my mobo can only focus on one of the cards at a time...

Can you try running your video card in that secondary x16 slot (x4 slot)? It could just be a bad slot, and then there;'s nothing you can do, since it's probably outside warranty period.

I had my GPU in the blue x16 slot and the RAID Controller in the black x16 slot.

Or if you can't get that working,m try turning on onboard video and putting the raid card in the pcie 3.0 x16 .slot.

Ditching my GPU isn't an option. If anything, I'm considering running a file server in a different computer.

I'm guessing that is didn't even detect the RAID card, correct?

per above, it detected it half the time.

Looking at the manaul for your board, it says this about the PCIe x4 slot:
"1 x PCI Express 2.0 x16 slot [black] (at x4 mode, compatible with PCIe
x1 and x4 devices)"

It doesn't say anything about it only working with video cards.

Asus telling you that it will only work with video cards either means that the person you talked to doesn't know what they are talking about or that they grossly misrepresented what the board actually supports.

They told me it'd work with the RAID Controller if I pulled the GPU out.

Looking further into the manual, have you tried turning on Option ROM Messages [Force BIOS] in the Boot menu?

I have not. I was hoping ASUS tech support would have given me stuff like this to troubleshoot with, but they just shut it down and told me I'm SOL.

And what about PCI ROM Priority? Setting it to Legacy might make it work.

I have not. I'll have to give it a shot. The Avagotech tech support agent told me to try LEGACY and to switch the PCIe from 3.0 to 2.0 or 1.0 in the BIOS config, but to confirm with ASUS tech support before doing so and after the phone call with ASUS, I stopped and started searching for a new mobo, and that's why I'm here now :\

You also have a UEFI/Legacy Boot option. Maybe changing it to "both" might help.

I'llve give it a shot.

Could be that the 3ware card will not work with a UEFI bios. (Upon further looking, it seems that that old 3ware card may not play nice with UEFI)

Does the 3ware card have the latest firmware on it?

Do you have the latest BIOS for your motherboard installed?

I don't know if the 3ware card has the latest firmware on it due to it being random as to whether it posted during boots. I was more focused on that then the firmware. I doubt my mobo has the latest BIOS on it as well. I typically keep things stock until I run into issues like these and was fully expecting ASUS tech support to troubleshoot the way you are.

I'll see if I can work on this and get back to you guys.

Real quick question before I do work on this.... the BIOS manual says that the PCIe x16 slots do share the same IRQ... would this prevent both cards from operating at the same time or is that something different?

 

[cyclone3d]

IRQ sharing shouldn't affect it at all unless the 3ware card is very picky.. which I can't see it being that way since it is PCIe. If it were plain PCI I could see that being more of an issue.

 

[apim]

You also have a UEFI/Legacy Boot option. Maybe changing it to "both" might help.

This worked. Thank you guys for the help!

 

[thesmokingman]

Man I haven't used the term IRQ in decades.