cancel
Showing results for 
Search instead for 
Did you mean: 

Funny business with PCI lanes on 9900k

mitropower
Level 7
Ok,

I am planning an upgrade of my rig (specs on left), and coming from 5930k with 40 lanes, all this business with 9900k having only 16 lanes is a real downer. Since I am not really keen on giving extra 500e for 9900X, because 5930k did not cost 1000e and had 40 lanes, I am looking at some options to get a rig better than I already have without selling my organs.

I am looking at Extreme XI, it attracted my for its DIMM.2 among other things. And I am a bit concerned that DIMM.2 riser card only seems to work directly on PCI lanes taking away 4x.
One of the things I plan on doing is going SLI and that will already push my GPUs config into x8/x8, if I also use DIMM.2 that will then push my cards into x8/x4 (how the hell does Intel consider 16 lanes CPU an enthusiast gamer CPU is beyond me).

So, ultimately can the riser card be redirected to use PCH instead? And even if so, how is that a good things? Is Maximus XI really not a good solution here because it will effectively offer lower performance to SLI customers because CPU ****blocks it? My train of thought is that if I use PCH for M.2 in order to dedicate CPU lanes to GPU, what does this board really offer that a lower priced does not (Formula is 50e cheaper, Hero half the price)? What am I not seeing?
1,747 Views
12 REPLIES 12

x-rated
Level 8
i think that dimm.2 wont use any of dedicated pcie lanes from cpu to vga, it will use the capacity from one memory channel as pcie x4
and there is almost no real difference (if any) between x8 and x16 on vga - i didnt notice that unless i saw gpu-z (i had sound card in the second slot for vga)

Menthol
Level 14
Any drives on DIMM.2 module will operate off the CPU, they cannot be changed.
Nvidia cards requires x8 lanes minimum, SLI will not operate at x4 like AMD cards
SLI support in games has been dwindling, hardly worth it unless you have a specific game that you cannot live without that requires SLI for playable frame rates at 4K.
You will not notice the difference in drive speed off the PCH compared to off the CPU in any normal use case. You will only see the difference in disk benchmarks and then very minor
A single 2080ti or Titan RTX would be a better choice than 2 lower end cards, and if you need 2 2080ti's a X299 or Threadripper system is a better choice

Yea, figured as much, just wanted to check first. It's so bizzare what Intel is doing. I guess its finally time to see what AMD has to offer.

panzlock
Level 12
Even an R7 2700 will be sufficient for your needs with 20 PCIe lanes. Mind you I agree, there's little good argumentation for SLI or Cossfire except bragging rights. "Look what I got, mutha futha!"
I'd like to deploy my troops in her country.

panzlock wrote:
Even an R7 2700 will be sufficient for your needs with 20 PCIe lanes.


Well, thats at par with 5930K I already have, so no point in giving money to get the same 🙂

As for bragging rights 🙂 nothing wrong with that 🙂

BossJ
Level 7
Hey - Mind if I hijack your thread? I think I understand what you are saying and I'm looking for possibly the same answer...

I'm moving from a 5930k / Maximus V Extreme to the XI Extreme with a 9900k - but I"m running SLI 2x1080ti's was going to go with a 970 EVO PRO Series NVMe...

is that not possible with this CPU?


(Sorry I haven't built a machine / followed hardware for awhile - except for GPUs...)

x-rated
Level 8
you can run both cards in x8 mode

x-rated wrote:
you can run both cards in x8 mode


With no NVMe drive? Correct?

x-rated
Level 8
SSDs can use another 24 lanes available from PCH 🙂