Question Pcie Lanes

[DefinitelyNotTom]

I've never built a pc and I keep forgetting how this works...

First off, it seems like mainstream cpus havew ay too few lanes, but anyway...

I have a 2700x cpu. Am I correct that I connect my gpu directly to the cpu, ie it doesn't use mobo lanes?

If so, why do some mobos have 2 pcie 3.0 x16? What types of compoents would be connected to them?

I'm basically asking all of this to see if an itx mobo is good enough for me. It has 1 pcie 3x16 and then it also has a m2.

I have a wireless card, but if I get this mobo, it has wifi built in.

So since I only have 1 ssd and 1 gpu, is there even anything I need an extra pcie 3x16 for? Seems like in the past when I was reading up on pcie lanes all of my components added up to needing more than the cpu itself supports.

 

[thx1138v2]

Here's a site that explains it pretty well: https://cotscomputers.com/blog/pcie-lanes/

You can have more lane s than are supported by the CPU because some lanes are implemented in the chip set. So the total lanes are chip set PCI lanes + CPU PCI lanes. So you need to check both specs.

 

[DefinitelyNotTom]

Here's a site that explains it pretty well: https://cotscomputers.com/blog/pcie-lanes/

You can have more lane s than are supported by the CPU because some lanes are implemented in the chip set. So the total lanes are chip set PCI lanes + CPU PCI lanes. So you need to check both specs.

isn't it also true, though, that the lanes used in the mobo are shared to where only x number of them (I think 4?) are used at the same time? So if I connect something other than only the ssd to it, the ssd would be sharing the lanes with whatever else (such as capture card.... which I doubt I'd add anyway, but just an example).

In other words, I think still you're tied to the cpu lanes, and the mobo lanes are shared to use the 4 lanes from the cpu.

 

[rgd1101]

ryzen cpu have 16 for gpu could run crossfire/sli as x8/x8
4 for m.2 drive

and correct chipset can be use differently on different motherboard, just need to read the spec