Honestly WTF does a PCI lane do?

[Brace]

So I'm planning on building my first ever computer sometime around June and I am planning on running one 980ti to start with but then upgrading to 2 in the future while also running an elgato game capture card in a PCI slot. I'm gonna use one of those new rumored Broadwell-E chips but I decide if I need the $150 more expensive 6850k over the 6800k because apparently the 6850k has 40 PCI lanes compare to 28 on the less expensive one. So my question is do I need the 40 lanes or would I not even utilize them. Btw I'll be using a Asus Deluxe X99 unless something newer and better comes out with the CPUs. Thanks.

[Enderman]

are you running four GPUs and extra expansion cards?

 

then no, you dont need 40 lanes

[TymmVonD]

So I'm planning on building my first ever computer sometime around June and I am planning on running one 980ti to start with but then upgrading to 2 in the future while also running an elgato game capture card in a PCI slot. I'm gonna use one of those new rumored Broadwell-E chips but I decide if I need the $150 more expensive 6850k over the 6800k because apparently the 6850k has 40 PCI lanes compare to 28 on the less expensive one. So my question is do I need the 40 lanes or would I not even utilize them. Btw I'll be using a Asus Deluxe X99 unless something newer and better comes out with the CPUs. Thanks.

A single 980 Ti benefits from all 16 lanes.

[boarder2k7]

Lanes are used to move data. Different speed devices need more or less lanes depending on what they need for data speed.

A GPU is x16 so 16 lanes.

Sound cards are x1 so one lane.

[alanz25]

your chip set also provides some pcie lanes

[alanz25]

[Blucyrik]

Trust me, 28 lanes is way more than enough for 2 GTX 980Ti's.

 

A single GTX 980Ti can't even utilize an entire PCIe 3.0 4x slot.

 

So, theoretically (if Nvidia didn't cap SLI on their cards to a minimum of 8x) you could run 4 GTX 980Ti's on an i5 6600k without any bottlenecks.

 

My point is, you'll be fine with any kind of consumer or enthusiast-grade CPU from Intel PCIe lanes won't be a problem for a long time.

[Brace]

Trust me, 28 lanes is way more than enough for 2 GTX 980Ti's.

 

A single GTX 980Ti can't even utilize an entire PCIe 3.0 4x slot.

 

So, theoretically (if Nvidia didn't cap SLI on their cards to a minimum of 8x) you could run 4 GTX 980Ti's on an i5 6600k without any bottlenecks.

 

My point is, you'll be fine with any kind of consumer or enthusiast-grade CPU from Intel PCIe lanes won't be a problem for a long time.

Ok thanks a lot I almost just wasted 150$ dollars.

[Blucyrik]

Ok thanks a lot I almost just wasted 150$ dollars.

 

Glad I could help! Let us know how the build turns out

[NumLock21]

Trust me, 28 lanes is way more than enough for 2 GTX 980Ti's.

A single GTX 980Ti can't even utilize an entire PCIe 3.0 4x slot.

That is bandwidth, not the physical number of lanes a gpu will use. Even a first gen x16 slot isn't fully saturated yet. But the board, isn't going to say, "hey your gpu isn't going to use up all of the bandwidth I'm providing to you.

I'll just turn that down a notch, and run your card at pcie 3.0 x4." When a gpu is installed, it will run at its full pcie spec, that's pcie 3.0 x16 or pcie 3.0 x8, regardless of the bandwidth the card is capable of saturating.

[typographie]

So my question is do I need the 40 lanes or would I not even utilize them.

 

Basically the difference is that having 40 lanes from the CPU allows you to run four-way SLI since 8x/8x/8x/8x is possible, whereas 28 lanes would "only" allow you enough lanes for three cards. AMD doesn't require an 8x connection for Crossfire, so I think four-way Crossfire is possible on 28 lanes in 8x/8x/8x/4x configuration. So as long as you aren't doing four-way SLI, you don't really need 40 PCIe lanes.

 

A single card in a PCIe 16x slot will only use up to 16 lanes no matter how many are available, and still doesn't fully saturate that much bandwidth.

 

Note that you have additional PCIe lanes from the chipset. So things like sound cards, PCIe SSDs, and wifi expansion cards generally have all the lanes they need regardless.