Available PCIE lanes (CPU v MOBO (PCH?)

[Big_M]

I'm at a loss. I'm looking at a new motherboard on a budget (ASUS H110 Plus) - which has:

"1 x PCIe 3.0/2.0 x16 (x16 mode, gray)
2 x PCIe 3.0/2.0 x1
3 x PCI"

So I thought a GPU which uses x16 dual slot should be ok, but then I read that this motherboard has only 6 lanes - so which is it? As above or 6 lanes?

The CPU I was going to use is the Pentium G4400 (again, on a budget) which has 'max supported' "16 (CPU) + 20 (PCH)" lanes which confused me further.

What IS the total amount of lanes available? How do I find this out myself? and what is the difference between CPU and PCH lanes?

I'm so confused and have been Googling it for what feels like hours!

 

[Inkiad]

All modern Intel CPUs provide at least 16 PCIe lanes. This is sort of pass-throwed to PCIe slot + M2 slots. Other PCIe lanes, which are extras are provided by motherboards PCH. So all modern consumer motherboards, including the Asus H110 plus has one PCIex16 slot.

EDIT: CPU pcie lanes are directly connected to CPU. Where as PCH lanes are connected to CPU via another chip called PCH. The bandwidth for PCH is limited. All device connected through PCH (like HDDs, extra USBs, PCIe) share that bandwidth.

 

[Big_M]

I'm still confused. If the Asus H110 Plus has a PCEe x16 slot, how can it have only 6 lanes? When I'm looking for GPU compatibility, what am I looking for? If all modern Intel CPUs have 16 PCIe lanes then, why does the PCH lane-count matter?

I don't know why I'm finding this so hard to get my head around...

 

[rgd1101]

gpu would use the 16 lane from the cpu.
the rest is from the chipset

 

[Inkiad]

The PCH is in motherboard. I am pretty sure by having 6 pcie lane it is trying to say that: Asus H110 PCH can offer extra 6 lanes, along with the CPUs lanes.

We need PCH lanes if you want to add an M2 SSD, add an second graphics card, need more USB ports than the CPU supports natively, SATA express slots etc etc.

 

[Big_M]

Right, so do some GPUs use more than 16 lanes? As in, would some CPUs offer more than 16 lanes for that purpose (or even offer more lanes for any other purpose?).

All I want is a GPU, HDD (yes HDD, not SSD!), memory and the CPU. Pretty basic. It's actually an assignment for college and we've only just touched upon components.

I want the HDD connected via SATA 6GB/s - I assume that's different from M.2?

Basically, if my GPU takes up 16 lanes, then the GPU is put into a x16 slot on the MOBO, but the lanes used come from the CPU, is what you're all saying - so the remaining 6 are still available for other expansions?

Why would, then someone need, for example, 20+ PCH lanes?

Sorry for so many questions, but I REALLY need to get this!