Should I Upgrade My Mobo (SLI currently 8x 8x)

After a tussle with Asus and their x99 Deluxe having killed my 5930k, I hastily replaced it with an MSI x99s Krait edition which matched my build and seemed to offer everything I needed feature wise. However, I have had to run my 2x video cards in 8x operation due to how the PCI-E slots are setup in that only slots 1 and 3 will allow for full 16x operation. I have 2x Strix GTX 1080s and having them in this orientation would put them right up against each other, which from a cooling perspective is far from ideal being non-blower style cards. I have been eyeing motherboards like the MSI x99 Godlike Carbon which from what I've read would allow having a few spaces in-between cards and still allow for full x16 operation for both cards, but my questions here are 1.) Is it worth it to replace a motherboard that, otherwise, has worked perfectly fine? and 2.) if so, what other motherboards should I look at as far as options goes? I'll list my full parts list below just for reference:

Mobo: MSI x99s Krait
CPU: i7 5930k (thankfully intel replaced the one that died)
GPU: 2x Asus Strix GTX 1080s w/ 4-slot High-Bandwidth Bridge
RAM: 16GB Corsair Dominator Platinum DDR4-2666 in quad-channel
PSU: Corsair RM1000i
Case: Silverstone FT02-BW Fortress 2
Storage: 512GB Samsung 950 Pro nvme M.2 drive, 500GB Samsung 850 Evo 2.5" SATA SSD, 4TB WD Black HDD
PCI Card: USB 3.1 type A PCI-e 4x card

I believe that's all the relevant info; having the nvme M.2 drive and the extra PCI-E USB card I went into this build knowing that having SLI and these other devices, I would be best going with a CPU with the 40 PCI-E lanes, however it seems like with running both video cards in x8 mode it has ended up being unnecessary. I've been contemplating whether or not to replace the motherboard for a while now, so any advice would be greatly appreciated.

x8/x8 is fine. Even 1080 doesn't saturate the full PCI-e 2.0 bandwidth, and 2.0 x16 is 3.0 x8... It's the same, so yeah.
If the mobo is fine, it's pointless to upgrade for SLI alone...


I had the same issue with my two old MSI 770s on my X99A Gaming 7 motherboard (also running a 5930K).

The top card was running hot as hell, so I asked MSI's support if I could move the bottom card down because the manual was very specific about how single-, dual- and tri-card setups should be done.
According to MSI, the cards would run at x16 + x8 if putting them in slot 1 and 5, not x8 + x8.

Still, doesn't matter, even a Titan XP won't saturate a PCIe 3.0 x8 connection so you won't be losing any performance.

That's what I figured. In my research it seems people swear that some weird obscure issues are due to their video cards operating in less than x16 mode, but I couldn't imagine that being the source of any issues or significant performance loss. I also like having my Intel nic instead of the options out there that are higher-end using the Killer nic which I don't necessarily want to deal with. Thanks for the advice!

The Killer E2200 is essentially a Quallcom Atheros AR8161 underneath, so with the right drivers and a bit of jumping through hoops during the installation you won't need all that Killer Suite nonsense etc. It just turns into a good NIC.
Still, I agree that the Intel NIC on the Krait is a lot less hassle.

My first post on this forum. :)

I'd like to get some more information on this pcie usage thing... I've wanted to ask for a while, but not really a social type... I just like to lurk around and search for my answers but couldn't find a definitive answer for this...

Does 16x16 make a difference now a days compared to 8x8? Should I get an x99 system and a cpu with 40 pcie lanes to achieve the 16x16 using SLi?

I have heard for a couple years and people still saying that running 2 video cards at 8x8 pcie lane usage doesn't matter compared to 16x16. Which is why I kept my 4790k instead of getting an x99 system. I didn't need anything more than a quad core. But then recently, I ran across this reddit thread.

There is also a link in the thread to a youtube video ( showing the differences in fps between 16x16 and 8x8 on couple games using 980Ti SLi.

So... the reddit thread and the youtube video shows there is some difference in some games, and pretty much no difference in some other games. but what caught my eye is the fps for the Division from the reddit thread.

The Division @1440p
16x16 HB - 77 / 146 / 119
16x16 - 74 / 145 / 113
16x8 - 70 / 131 / 95

So... now, I currently have a 4790K, 2x Titan XP and a M.2 NVMe ssd in an M.2 slot on an Asus z97 Deluxe. The motherboard states that the M.2 uses the slot 2 lanes. My video cards are in slot 1 and 3. I was fairly happy with this setup running most of my games at 4K max settings at above 60 fps. Except that in gtaV and fallout4 sometimes dips below 60, and the Division can barely stay above 80 with dips to 50 at 1440p... at 1440p. I figured it was just a poor optimization thing.

Could it be that using the M.2 ssd is holding back the performance somehow on my particular system? Will getting an x99 system with a 40 lane cpu actually improve performance?

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It's not worth because to get two x16 slots you'll be using a PLX chip that would introduce latency into the system and would only give you more "fake" lines. Nvidia SLI is designed to work with x8 lanes without performance issues (just talking about raw performance in benchmarks and not in real life situations where softwares are responsible for SLI optimizations).

@nuguu The lower framerate is due to the latency introduced by the PLX chip to achieve two x16 connections. That's why on consumer and gaming board PLX chips are not used. If you're doing just crunching numbers with videocards the latency of the PLX chip is not an issue but if you're aiming to get out those numbers as fast as you can (frames for a videogame) there are some "issues".

You should be fine

Thats ea for you

Thats bethesda for ylu

Yeah, I'm kind of on the fence about whether or not I should have gone all out with 1080s in SLI at this point, I haven't seen a game since Witcher 3 really use SLI to its fullest potential. But that's for another thread I guess.

I was just so disheartened with Asus after my experience with the x99 Deluxe and their support that I wanted to just get something not-Asus asap to get my rig up and running, so I'm glad that my pick of the MSI board didn't really hinder me in any meaningful way. Granted, I still got the Asus flavor of 1080s after that, but I've had experience with Strix cards and felt confident in them compared to another motherboard.