Understanding PCIe abstraction

Just finished putting my build list together and decided to double-check if everything actually works together. Now I’m staring at this whole PCIe lanes thing, which is basically Greek to me. If I'm reading this right, my CPU doesn't have enough PCIe lanes to handle all the gear I picked out. Can someone tell me if I'm tripping? And if I am, is this actually a dealbreaker?

MOB:
ASRock X570 Creator:
3x PCIe 4.0 x16 (1x x16, 1x x8, 1x x4), 3x PCIe 2.0 x1, 1x M.2 / M-Key (PCIe 4.0 x4, 22110/2280/2260), 1x M.2 / M Type (PCIe 4.0 x4 / SATA, 22110/2280/2260/2242/2230), 1x M.2 / E-key (PCIe, 2230, with WiFi + BT module)

CPU: AMD Ryzen 7 3900x:
24x PCIe 4.0 (16 + 4 + 4), 16x for GPU

SSD (two of them):
M.2/M-Key (PCIe 3.0 ×4)

GPU (2080 Ti):
PCIe 3.0 ×16

Someone told me the CPU has 24 lanes, but since the SSDs want 8, the GPU wants 16, and the chipset takes 4, the CPU is short by 4. I honestly thought the chipset had its own dedicated lanes and wouldn't be stealing from the CPU's stash.
Also, I'm assuming stuff like RAM doesn't really factor into the PCIe lane count.
Thanks.

Does the GPU actually drop down to x8 when you have two M.2 drives running simultaneously, or does one of those drives just pull its bandwidth from the chipset instead? It’s surprisingly tricky to find a definitive answer online. Maybe you could just fire up GPU-Z and check if the graphics card actually hits x16 while you're putting it under a heavy load?

wanderingbison9 said:Does the GPU actually drop down to x8 when you have two M.2 drives running simultaneously, or does one of those drives just pull its bandwidth from the chipset instead? It’s surprisingly tricky to find a definitive answer online. Maybe you could just fire up GPU-Z and check if the graphics card actually hits x16 while you're putting it under a heavy load?

Thanks guys. I'll figure it out.

Gregory Anderson34 said:Just finished putting my build list together and decided to double-check if everything actually works together. Now I’m staring at this whole PCIe lanes thing, which is basically Greek to me. If I'm reading this right, my CPU doesn't have enough PCIe lanes to handle all the gear I picked out. Can someone tell me if I'm tripping? And if I am, is this actually a dealbreaker?

MOB:
ASRock X570 Creator:
3x PCIe 4.0 x16 (1x x16, 1x x8, 1x x4), 3x PCIe 2.0 x1, 1x M.2 / M-Key (PCIe 4.0 x4, 22110/2280/2260), 1x M.2 / M Type (PCIe 4.0 x4 / SATA, 22110/2280/2260/2242/2230), 1x M.2 / E-key (PCIe, 2230, with WiFi + BT module)

CPU: AMD Ryzen 7 3900x:
24x PCIe 4.0 (16 + 4 + 4), 16x for GPU

SSD (two of them):
M.2/M-Key (PCIe 3.0 ×4)

GPU (2080 Ti):
PCIe 3.0 ×16

Someone told me the CPU has 24 lanes, but since the SSDs want 8, the GPU wants 16, and the chipset takes 4, the CPU is short by 4. I honestly thought the chipset had its own dedicated lanes and wouldn't be stealing from the CPU's stash.
Also, I'm assuming stuff like RAM doesn't really factor into the PCIe lane count.
Thanks.

The chipset does have its own lanes, but the catch is that the connection between the CPU lanes and the chipset lanes is relatively slow. Because of that bottleneck, you really want to plug anything important directly into the CPU lanes.

Since we're looking at 24 PCIe 4.0 lanes, you shouldn't see any real bottlenecks even if one of those SSDs is running through the chipset.

Based on this, the second M.2 should be routed through the chipset.
https://www.heise.de/imgs/18/2/6/8/8...35c7dc881b.png

Just put it all together and run the benchmarks.

So, if I'm reading this diagram correctly, doesn't it look like we get a 2x multiplier if we're running two NVMe drives? (Just pick one of those boxes at the bottom)

wanderingbison9 said:So, if I'm reading this diagram correctly, doesn't it look like we get a 2x multiplier if we're running two NVMe drives? (Just pick one of those boxes at the bottom)

No, no, that’s only if you have two NVMe drives running through the chipset. X570 motherboards have enough lanes to hook up just about anything.

A single x4 or a split 2x2 comes straight from the CPU. This setup is separate, so it'll be x4, but it's going to be sharing bandwidth with everything else on the chipset.

Alright, I see people are saying there isn't any bottlenecking when pairing a Ryzen 3000 series chip with the chipset.

Gregory Anderson34, don't sweat it. Everything you're putting together is going to work perfectly fine.

Thanks for all the help, everyone!!

Thanks for the help, everyone!!