pci-e PCI-e Limit Question

[FastRDust]

So i want to make a small gaming pc, i have the GPU ( GTX1080)

But i need the rest, I was looking at the I5 9600K but i see that this one only supports 16 PCI-e Lanes.

 

So if i where to have the GPU in an x16 and add a M.2 Storage.

This would mean that the M.2 uses 4 lanes and the GPU only gets 12 Lanes?

 

Would this really impact GPU performance later on if i would upgrade to the RTX series later on?

 

BTW the computer would just be used for Gaming only, nothing fancy like 4K But will be used for VR.

[NelizMastr]

It depends on how the M.2 is wired. If it's connected to the CPU, your GPU will run at 8x. If it runs via the PCH you'll run at full bandwidth. Impact is zero with current gen hardware.

[FastRDust]

Just now, NelizMastr said:

It depends on how the M.2 is wired. If it's connected to the CPU, your GPU will run at 8x. If it runs via the PCH you'll run at full bandwidth. Impact is zero with current gen hardware.

If it runs through a PCH it would mean that it will run at Sata speeds correct?

[Dujith]

The 16 PCI-E lanes are what are available for GPU's

 

Edit: Some motherboards do have a M2 directly from the CPU. Tho most will use the DMI 3.0 (PCIE x4) bus and that does not substract from the 16 lanes in the spec.

[NelizMastr]

4 minutes ago, FastRDust said:

If it runs through a PCH it would mean that it will run at Sata speeds correct?

Nope. The PCH has 4 PCIe lanes, so the SSD will run at full speed.

[FastRDust]

3 minutes ago, NelizMastr said:

Nope. The PCH has 4 PCIe lanes, so the SSD will run at full speed.

this is not really easy to search for as many motherboard resellers do not add this kind of information XD

 

Thanks though, no i can at least do some more research on this

[DildorTheDecent]

1 minute ago, FastRDust said:

this is not really easy to search for as many motherboard resellers do not add this kind of information XD

 

Thanks though, no i can at least do some more research on this

Look on Intel ARK for the PCI-E lane spec for whatever chip set you're running.

 

The motherboard manufacturer will also have the manual available online which will tell you how the slots are wired.

[FastRDust]

1 minute ago, DildorTheDecent said:

Look on Intel ARK for the PCI-E lane spec for whatever chip set you're running.

 

The motherboard manufacturer will also have the manual available online which will tell you how the slots are wired.

I Doubt that a Budget chip like the I5 9600K will support this though.

[Dujith]

5 minutes ago, FastRDust said:

I Doubt that a Budget chip like the I5 9600K will support this though.

I wouldnt call that CPU a budget chip. Not at that price and performance.

Besides even the lowly celeron CPU will have 16 lanes and almost all the features of its bigger brother.

[DildorTheDecent]

6 minutes ago, FastRDust said:

I Doubt that a Budget chip like the I5 9600K will support this though.

Intel ARK has the spec for just about every processor and chipset in the last 10+ years.

 

Near every motherboard manufacturer has there manuals online.

 

Most storage devices run through the PCH anyway. It'll support it.

[FastRDust]

1 minute ago, Dujith said:

I wouldnt call that CPU a budget chip. Not at that price and performance.

Besides even the lowly celeron CPU will have 16 lanes and almost all the features of its bigger brother.

Even most of the I7 chips are limited to 16 Lanes.

Only Xeons and the I9 seem to go past that amount of lanes or the I7 ****X series

Just now, DildorTheDecent said:

Intel ARK has the spec for just about every processor and chipset in the last 10+ years.

 

Near every motherboard manufacturer has there manuals online.

 

Most storage devices run through the PCH anyway. It'll support it.

I'm not really worried about the performance of the storage, i just don't want it to interfere with the GPU and cause hiccups ore something XD

[Dujith]

7 minutes ago, FastRDust said:

I'm not really worried about the performance of the storage, i just don't want it to interfere with the GPU and cause hiccups ore something XD

Even if the M2 would be from the CPU (leaving 12 Lanes for the GPU) it would not interfere with the GPU as the 12 lanes would be separate from the 4 for the M2. Otherwise a SLI setup would have the 2 cards fighting eachother , the lanes are separate.

[FastRDust]

1 minute ago, Dujith said:

Even if the M2 would be from the CPU (leaving 12 Lanes for the GPU) it would not interfere with the GPU as the 12 lanes would be separate from the 4 for the M2. Otherwise a SLI setup would have the 2 cards fighting eachother , the lanes are separate.

Wouldn't it then go to 8x lanes?

[Madgemade]

Yes it would go to 8x for the GPU, this makes no difference unless you have a very fast GPU and CPU which you don't. Linus has done videos on 16x to 8x look at them to be reassured.

 

Mostly PCH lane run at Pcie 2.0 not 3.0. But mostly M.2 slots are connected directly to the CPU not through the chipset and use 4 lanes as said above so you won't have any problems. Regardless there will be no "interference" between anything. That isn't possible, the only thing that can change is the number of lanes and this make very little difference except for really high end systems.

 

What motherboard do you have (or plan to buy) if we know then it will be easy to say 100% if PCH is used or not because it will all be explained in the manual.

[Dujith]

6 minutes ago, FastRDust said:

Wouldn't it then go to 8x lanes?

Yes, my point was more about how the PCIE lanes are separate from eachother.

[FastRDust]

2 minutes ago, Madgemade said:

What motherboard do you have (or plan to buy) if we know then it will be easy to say 100% if PCH is used or not because it will all be explained in the manual.

Good point, I was looking at a GIGABYTE Z370P D3 or the MSI Z370-A Pro

[Dujith]

The Gigabyte one has 1 M2 slot and its controlled by the chipset

The MSI also has 1 and also controlled by the chipset

[Madgemade]

I had a look at the I5 9600K is not in the supported list for the GIGABYTE Z370P D3. MSI apparently added support for their motherboards, but you might need an older CPU to actually update the BIOS? Probably better to buy a Z470 board.

 

Also all CPUs for 1151 use 16 lanes. Nothing has any more lanes, the i7 is the same 16 lanes. There's nothing to worry about and as far as I can tell if use your M.2 is the motherboards M.2 slot then it will run at full speed and the graphics card will also be 16x full speed. This is all managed by the chipset. Only if you put something in the second x16 slot will then graphics card drop to 8x. Adding an M.2 SSD will not make the graphics card lose speed on those motherboard or on Z470 boards.

 

If you really want your M.2 to be attached to the CPU then you will need to buy a Threadripper or Intel enthusiast system costing massively more. Chipset is part of how it works it doesn't make any meaningful difference in speed. Like I said nothing to worry about it will work fine.

[FastRDust]

1 minute ago, Madgemade said:

I had a look at the I5 9600K is not in the supported list for the GIGABYTE Z370P D3. MSI apparently added support for their motherboards, but you might need an older CPU to actually update the BIOS? Probably better to buy a Z470 board.

 

Also all CPUs for 1151 use 16 lanes. Nothing has any more lanes, the i7 is the same 16 lanes. There's nothing to worry about and as far as I can tell if use your M.2 is the motherboards M.2 slot then it will run at full speed and the graphics card will also be 16x full speed. This is all managed by the chipset. Only if you put something in the second x16 slot will then graphics card drop to 8x. Adding an M.2 SSD will not make the graphics card lose speed on those motherboard or on Z470 boards.

That was what i needed to know because i though the m.2 slot was inline with the PCI-e x16 Lanes and this shared bandwith with them.

So on to look for a Z470 Board