MSI X99S Gaming 7, i7 5820K & 2x 780TI in SLI

[Chaosphenom]

Hi,
I have the above configuration, I was under the impression I should be getting 16x on one card and 8x on the other but it seems I am only getting 8x on both.

 

[TheDualshock]

According to their specs :

4 x PCIe 3.0 x16 slots, support up to 3-way mode
- 1-way mode: x16/ x0/ x0/ x0
- 2-way mode: x16/ x16/ x0/ x0*, 16/ x8/ x0/ x0**
- 3-way mode: x16/ x16/ x0/ x8*, x8/ x8/ x8/ x0**
* For the CPU that supports 40 PCIe lanes
** For the CPU that supports 28 PCIe lanes

You should actually be getting x16 and x8 on those 780Tis in SLI assuming they are in the right slots. Are you checking with GPU-Z? Run the render test to see if it jumps back to normal.

 

[chenw]

According to the Manual, when using 2-Way SLI with 5820k, they should go into E1 and E3 slots (IE right next to each other). The first slot goes down to X8 if the E5 slot is occupied.

(All in all I find the lanes layout on that mobo a little odd).

Side question, sorry for hijacking, is there any tangible benefits to run X16/X8 over X8/X8? I had always thought the X16 card would be bottled by the X8 on the second card

 

[Chaosphenom]

According to the Manual, when using 2-Way SLI with 5820k, they should go into E1 and E3 slots (IE right next to each other). The first slot goes down to X8 if the E5 slot is occupied.

(All in all I find the lanes layout on that mobo a little odd).

Yea I've sorted it now, I had it in the wrong slot, although this seems VERY odd to me as there is no space between the 2 cards which means the top one is just blowing straight onto the bottom one. Its a poor layout tbf. Now if I can get get it to boot quicker it seems to take a while to boot even thought its got a new SSD and fresh install of windows 8.1.

 

[TheDualshock]

Side question, sorry for hijacking, is there any tangible benefits to run X16/X8 over X8/X8? I had always thought the X16 card would be bottled by the X8 on the second card

There isn't a big performance difference with running your card in a PCIe 2.0 x8 over a x16 one, 5%~ at most. For PCIe 3.0, it doubles the bandwidth of PCIe 2.0 which means that PCIe 2.0 x16 is equivalent to PCIe 3.0 x8 etc. (if not mistaken).

 

[TheDualshock]

Yea I've sorted it now, I had it in the wrong slot, although this seems VERY odd to me as there is no space between the 2 cards which means the top one is just blowing straight onto the bottom one. Its a poor layout tbf. Now if I can get get it to boot quicker it seems to take a while to boot even thought its got a new SSD and fresh install of windows 8.1.

You might be able to reduce the POST time by enabling a setting presumably in the Boot section of the BIOS. Something around the words "Fast Boot" may help your boot times by reducing that post screen.

 

[Chaosphenom]

I am now getting another issue, I am getting the following codes when I boot up the PC before the MSI BIOS screen.
9C
B4
A2

 

[Dooshe Nozzle]

Does it still boot? I get these exact codes prior to the mobo splash screen and have no issues. I believe they are just status codes to indicate where the motherboard is in its startup processes.

 

[romedyMC]

Related question: Do your cards boot with max fan speeds when in the _1 and _3 slots? I have a pair of Gigabyte 780s and am unable to boot up when I have both cards installed, but it boots fine with either card on its own.

I also get the exact same codes at startup.