How to choose an AM5 motherboard that prevents GPU drop when using many M.2 slots?
How to choose an AM5 motherboard that prevents GPU drop when using many M.2 slots?
I'm new to building PCs and I'm a bit puzzled about how the X670E motherboards use PCIe lanes with a 7950x, especially since most people don't use more than two M.2 drives.
For my build, I plan to run a more specialized setup and will need to fill three SSD slots. I intend to use a 1TB 990 Pro for Windows, apps, and unsorted files, a 2TB SN850X for games and mods, and an Acer Predator GM7000 4TB for 3D assets, textures, and video editing. I might add another SSD later, but not right away.
The 7950x offers 24 PCIe lanes to the CPU's connections, with the remaining four slots going to the chipset. For instance, if a motherboard has two PCIe 5.0 x16 expansion slots (only one used) and two of the four SSD slots are PCIe 5.0 x4, filling those slots with 4.0 x4 NVMe drives could affect GPU performance—specifically, whether running at x8 is feasible. This question comes from forum discussions, but without official diagrams, I want to understand how this setup works.
From other users' experiences, it seems the 7950x has a limit on the number of PCIe 5.0 connections it can support naturally. If I'm not using any PCIe 5.0 slots, does that really affect my SSD configuration? If so, would having four PCIe 5.0 connections be ideal? Would running four used 5.0 slots at x8 hardware actually work?
Welcome to the forums, newcomer!
You can check out this resource:
View: https://www.youtube.com/watch?v=pUUVW7wgR3s
For an example of a board with three M.2 SSD slots, you can see:
https://pcpartpicker.com/product/FcbRsY/...50m-pro-rs
One of the slots will run at Gen4x2 speeds, while the others will be Gen5x4 and Gen4x4.
My question is, do you really need all those high-end SSDs? In practice, it’s unlikely you’ll notice a difference unless you’re frequently switching between heavy tasks like gaming or large data loading. The 990Pro seems unnecessary; you could easily run the OS on a PCIe 3.0x4 SSD and still be fine.
Also, please don’t forget to share more about your setup, location, or budget. That will help us better tailor suggestions and give you useful follow-ups.
PCIe performance and lane counts are separate aspects. Installing a PCIe 1.0 4x card still utilizes the same number of lanes as any other PCIe revision.
The processor supports 24 lanes, with four dedicated to the chipset; the chipset itself has additional lanes, and in the X670E model it connects to another chipset.
This setup means multiple devices vie for bandwidth rather than direct connections to the CPU.
To ensure optimal drive speeds, connect them directly to the CPU—such as 8x for the GPU, two 4x SSDs in the primary x16 slot, and reserving an M.2 slot for the CPU.
If your data demands are more common, simply insert drives into any available M.2 slots without conflict with the GPU option.
In short, consult your motherboard manual for specific details or refer to Newegg.com’s specifications page for guidance.
This is the most affordable board providing three 4x lane M.2 drives.
Here’s the revised version maintaining the original structure and details:
I’ve prepared my current build plan as shown here:
https://imgur.com/a/7E9TkOw
Since I’m based in the US, pricing and availability shouldn’t significantly impact me. My budget for the PC is roughly $3,600 to $3,900, with peripherals adding about $4,500±. I’m aiming to bring the total down to the lower $3,000 range, though I’m open to purchasing a system rather than upgrading it for over four years beyond storage needs.
My reasoning for each component is as follows:
AIO: I prefer not to include an air cooler for general noise, and even if I undervolt the 7950x, I want confidence in running my CPU during overnight rendering.
7950x: Benchmark videos confirm it isn’t the top choice for gaming, but it performs well in 3D tasks.
X670E-A Gaming Wifi: Still uncertain, as this is the most debated part of my build, especially with multiple SSDs and GPU performance demands.
RAM: There’s a lot of discussion about DDR5 on AM5, and I’ll need a solid amount for video editing.
SSD's: I require ample storage and have specific organization needs.
4090: A 4080 Super or lower would work, but the VRAM is crucial, and AMD GPUs don’t match up with RTX cards for 3D rendering.
Case: Aesthetics matter a bit, lol
PSU: I might eventually add HDDs in RAID if I really need them.
Additionally, I’ve started earning from 3D work using my Mac, and as I push its limits, I realize I’ll eventually want a high-end PC. I can only optimize so much in Blender.
Regarding SSDs, I definitely don’t need the latest models and will have to adjust the price accordingly. But for 3D and video work, unpacking projects, loading 8K textures, and importing 4K renders for editing and color grading will take a toll over a few days, and I want to avoid it.
Thank you for your message. I've shared my build plan in my reply to Lutfij recently. Right now, I'm considering the Asus STRIX X670E-A Gaming Wi-Fi, while the manual lacks detailed block diagrams and SSD setup guidance. It features three PCIe 5.0 slots—one for the GPU and two M.2 slots linked to the CPU. The remaining two M.2 drives connect via PCIe 4.0 x4. I'm unsure if any ports share bandwidth or if there are specific configurations needed for SSD and GPU separation on this board.
The memory you selected was meant for Intel XMP settings. You should opt for the alternative instead. The two 4.0 slots are suitable for use. However, the instructions aren't very clear. It's simple to verify when installing and ensure the PCIe lane count on your GPU is correct, swapping it if necessary. The board only provides a 4x x16 slot plus one extra, so they likely didn’t plan for much interference with the GPU.
For rendering tasks and similar applications, the lane count has minimal impact. It would only slightly affect high-resolution or texture-heavy games.
I don't support liquid cooling for systems focused on profit. A large air cooler would be more practical.
You are utilizing 24 PCIe lanes, which can be accessed via the CPU, allowing for 16 GPU slots with 2x X4 M.2 drives. The M.2 slots themselves do not limit performance. Overall, there are four M.2 slots and six SATA ports at 6Gb/s. This configuration works with AMD Ryzen™ 9000 and 7000 series processors. The M.2 slots support PCIe 5.0 x4 mode in all variants.
AMD X670 Chipset
M.2_1 slot (Key M), types 2242/2260/2280 (compatible with PCIe 5.0 x4)
M.2_2 slot (Key M), types 2242/2260/2280 (compatible with PCIe 5.0 x4)
AMD Ryzen™ 8000 Series Desktop Processors
M.2_1 slot (Key M), type 2242/2260/2280 (supports PCIe 4.0 x4 mode)
M.2_2 slot (Key M), type 2242/2260/2280 (supports PCIe 4.0 x4/x2 mode)
Editing provides 28 lanes of on-chip PCIe®Gen5, offering 24 usable lanes when paired with B650 or X670 chipset.