Regarding PCIE lanes

[Avok]

So I have been making some plans with a friend on upgrading his desktop. He already has decided on graphics as he has 2xRTX 2080 Ti, and the only thing that remains is choosing a CPU. At first we thought of getting a 9900K but I noticed that it only has 16 PCIE lanes available. He claims that it won’t be necessary to go for another CPU but I believe he should go for sth better as he already has the best GPUs he could already. Should we opt for another CPU that covers 32+ lanes or it won’t make such a difference in terms of performance?

[KarathKasun]

2080 Ti SLI sees a performance drop when going form X16/X16 to X8/X8.

2080 is about as far as you can push on an x8/x8 setup without losing performance.

 

You need an HEDT setup (Threadripper or i9 X series) with appropriate CPU and MB to get more than 32 lanes.

[SidM]

I'm not exactly an expert on this subject, but you need to run both the cards in pcie 3.0 x8(this will not allow you to use any nvme pcie drives tho)

[SidM]

Btw, just a tidbid of knowledge, running modern gpu in 8x or 16x will make barely if not any difference in performance, this is bcuz the cards are not able to saturate that high  bandwith to the limits

[KarathKasun]

2 minutes ago, SidM said:

Btw, just a tidbid of knowledge, running modern gpu in 8x or 16x will make barely if not any difference in performance, this is bcuz the cards are not able to saturate that high  bandwith to the limits

2080 Ti breaks from this, and does see a performance reduction.

[SidM]

3 minutes ago, KarathKasun said:

2080 Ti breaks from this, and does see a performance reduction.

Minimal performance reduction, btw doesn't chipset provide additional 4 or 8 lanes?

[SidM]

btw can u help

[GoldenLag]

17 minutes ago, KarathKasun said:

2080 Ti breaks from this, and does see a performance reduction.

Does it? The biggest GPU the Titan V barely gets an reduction. Edit: and only in certain loads

 

 

28 minutes ago, Avok said:

He already has decided on graphics as he has 2xRTX 2080 Ti

Dont. SLI/Crossfire os truly not worth it. Even though you wont see a performance reduction from 8x.

 

28 minutes ago, Avok said:

At first we thought of getting a 9900K

If he is spending a lot of money on a pc right now. Kd suggest waiting for Zen 2. Spending big consumer CPU money atm isnt the wisest with Zen 2 right around the corner. 

[KarathKasun]

39 minutes ago, SidM said:

Minimal performance reduction, btw doesn't chipset provide additional 4 or 8 lanes?

Chipset has 4x connection to CPU and I think 8x for devices.  Anything connected to it performs like an x4 device or worse.

 

24 minutes ago, GoldenLag said:

Does it? The biggest GPU the Titan V barely gets an reduction. Edit: and only in certain loads

Up to 25% difference depending on the load...

https://www.gamersnexus.net/guides/3366-nvlink-benchmark-rtx-2080-ti-pcie-bandwidth-x16-vs-x8

[Avok]

Well which CPU or series would you propose?

[KarathKasun]

Any of the following with 44 PCIe lanes and fits your budget...

https://en.wikipedia.org/wiki/List_of_Intel_Core_i9_microprocessors

 

Or any Threadripper that fits your budget...

https://en.wikipedia.org/wiki/List_of_AMD_Ryzen_microprocessors

[HoneyBadger84]

I mean, honestly, this is one of the worst times for someone to build a 2x 2080 Ti build. X599 is just coming out, Ryzen 3 and Gen 4 pcie is close. Yikes. I would build a simpler machine and wait for the big socket stuff then upgrade to that in your place. Running in x8 x8 is going to effect performance a bit, but with that much raw power who cares.

 

A 9900k build if he's got money to throw around is a great crossroads, and he can resell it easily when he goes for next gen TR4 or Intel's next HEDT setup later.