Looking to upgrade. Concerned about PCIe lanes

Hello guys,
I'm looking to do a minor upgrade on my system, but I am concerned about PCIe lanes.
My current configuration is:
Intel 4770K
MSI mPower Max Z87
XFX R9 290
32GB Corsair Vengeance Pro
Samsung 850 Pro

I'm very satisfied with the gaming performance of this CPU so I don't really feel the need to upgrade the CPU, however one of its problems is that it only has 16 PCIe lanes. I'm looking to go crossfire with some of the newer Radeon GPUs and I also want to swap that sata SSD for an m.2 SSD like the Samsung 950 Pro. I can't go SLI + m.2, because nVidia requires you to have at least x8 lanes per GPU slot for SLI certification (AMD doesn't yay). If I go crossfire + m.2, that would mean that I will go at GPU1 (x8), GPU2 (x4), m.2 (x2)? (Not sure if this motherboard supports m.2 x4 or m.2 x2) Can't find info on the product page. Most likely the motherboard doesn't have an actual m.2 slot and what I thought was m.2 is actually mSATA, since that's the only thing mentioned on the product description page. So if I want to use an m.2 drive, I will have to use an adapter like the Lycom DT-120 adapter. If this is the case I won't be able to boot from this drive so this upgrade will be pretty much useless.

So in summary:
Don't want to change the CPU, but I only got 16 PCIe lanes.
If I go GPU + GPU + m.2, I will get x8, x4, x2 or x8, x4, x4

P.S.
Some motherboards have some weird instructions like:
"The PCIE_X8_4 slot shares bandwidth with M.2 x 4. When PCIE_X8_4 is occupied, the M.2 will be disabled."
"The PCIE_X8_4 slot will be disabled when using a 28-Lane CPU"
"The PCIE_X4_1 (gray) slot shares bandwidth with the PCIE_X1_1 slot, USB3_E910, and SATAExpress_E1 connector. When the PCIE_X4_1 slot is occupied by an X1 or X2 device, the SATAEXPRESS_E1 will be disabled. When the PCIE_X4_1 slot is occupied by X4 device, both the SATAEXPRESS_E1, USB3_E910 ports, and the PCIE_X1_1 slot will be disabled.

I have to check mine for that kind of crap as well...

Following is a very stupid question:
Does game resolution affect the bandwidth output of the GPU? For example do the GPUs require more bandwidth when playing in 3440x1440p than when playing in 1080p? Thanks x2.

You need a board with a PEX chip that allows PCIE lane switching. They are more expensive because of the chip. Might be hard to find for previous generation CPU's. As far as I know, modern gpu's haven't come to the point where they are saturating the bandwidth on PCIE x8 lanes yet, regardless of the resolution. But, it does take higher bandwidth to push higher resolution at a higher frequency. That might start to change with the performance increase coming with the next gen GPU's and new display technologies.

If you are looking at a specs on a board that says

More than likely, this is an X-99 board and will not work with your CPU. It's socket LGA 2011-v3. Your cpu is a sockett LGA 1150

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Thank you @Knight26, no point in investing too much in old hardware. My goal is to use the same CPU and maybe even the same Mobo, since they are old, but still enough for gaming. Maybe the sane thing to do is to only upgrade the GPUs, and instead of an m.2 to go with a x2 SATA SSD raid0 which won't be as fast, but would be noticeable still.
This way I will have x8 x8 for my GPUs and won't have to upgrade the board. Am I correct?
Thanks.

Uprading the GPU's will be the easiest way to boost your gaming performance. You probably won't tell much difference between raid0 ssd's vs the single 850 pro in real world application. There's a vast difference in the benchmark numbers of course, but raid0 ssd's operate differently than a single ssd would so you would still be operating at single ssd speeds for most tasks other than pure data storage and transfer. I would only do a ssd raid0 if you want to increase the capacity without shelling out a lot for a higher capacity ssd and you are not worried about loosing the data on those ssd's because if one fails then everything is lost. I've been thinking about doing that to increase capacity for my game libraries. If an ssd fails I can always replace it and download my games again.

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I will only be using the raid0 for OS and games, the rest of my data is on an HDD. However most of my games are on my HDD as well since the SSD is so small, so I might add an additional SSD just so I can play more games from the SSD. This way even if the raid0 doesn't improve level loading times, the SSD will still improve it over the HDD.
Thanks a lot for your advice @Knight26, I know how I'm going to proceed now.

I find myself in your exact situation, where my 4770k is more than enough for gaming but I want the latest technologies in storage and dual gpus configs.

With research and experimentation on my part I found out that I should just give up on the dual gpu configs anyway, since most of the games I play do not really benefit from dual gpus. What games do you want to play? Think about upgrading to a single card.

Your CPU only has 16 pcie lanes but your chipset also contributes pcie lanes to the system (though I don't know off hand how they are allocated on your motherboard so I'm not sure if the chipset handles the pcie lanes to the m.2 or not).

Anyways... here's a great read if you want to understand how pcie lanes affect gaming performance
https://www.pugetsystems.com/labs/articles/Impact-of-PCI-E-Speed-on-Gaming-Performance-518/

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@Cavemanthe0ne, this is a decent idea. The board itself is quite expensive $500+, but I see some used ones for less than $200. Such board will allow me to use the 4770K for a much longer time and be able to go crossfire/SLI and m.2 x4 as well. I don't care about DDR4 because it doesn't make much difference for gaming.

@DeathSpell, read my reply to @Cavemanthe0ne, this is probably the best way to go if you are willing to spend $200-300. You will be able to use the latest m.2 x4 with this setup. I'm expecting most new games to be able to utilize SLI/Crossfire configs especially if you are aiming at 60+ FPS gameplay @ 3440 x 1440p, I'm also looking into VR which appears to be quite power hungry as well.

Very interesting read, seems like it does not make much of a difference, x16 or x8 for the 2nd card

I remember Wendell saying something similar but I can't remember if it was in the Tek or a motherboard review

It doesn't matter for the first card either.

You can install a faster SSD in the PCIE_x4 slot. Surely would be faster than a standard SSD but not as fast as a NVME drive but still an upgrade. Or, if you're not concerned too much, just go for a 3x SSD RAID0 array and call it the day. With another 2 Samsung drive you'll get roughly 1500MB/s, wich is pretty nice I guess.
To be honest I think that 90% of the users won't notice the difference between a NVME drive and an SSD, because the bottlenecks and slowdowns are due to poor code optimization, weak memory management and stuff like that. I wouln't bother too much for storage speed to be honest.

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Is it true that the PCIe lanes for stuff like M.2 and PCIe storage drives are handled by the chipset EVEN by boards that do not have a PLX chip? Meaning that the storage doesn't affect CPU PCIe lanes and GPU bandwidth?

There are some pcie chipset lanes. Also before you buy nvme ssd, older chipsets gets you pcie 2.0 lanes which are half the bandwith so it will be bottlenecked if it works(still it would be faster than sata ). also it migth not be bootable at all or you will have to do same tricks to make it bootable (cloning os to it etc)But there are some m.2 ssd for pcie 2.0 too like xp941, not so fast but still faster than sata drives both sequentials and random read and writes.

If on the manual is not stated that those lines are shared with the CPU you're good. As ignx said those are handeled by a separate controller that's also handling some fron USB connectors (reading what you posted). I bet that the controller handling those PCI lanes is an AsMedia controller of some sort.

@Cavemanthe0ne The Gigabyte board doesn't have an m.2 slot. I'm guessing one would need to add the m.2 with a PCIe adapter? Is this going to be as efficient? Is it going to be bootable?
Thanks.

Do you there is a HUGE benefit to M.2 x4? Is this upgrade, something that one would really notice in real world applications like Game loading times?

Unless there is a huge benefit, then I think I will keep the current mobo, upgrade to 1TB ssd and get some new GPUs.