Is there a x299 Motherboard with m.2 PCIe socket connected straight to the CPU?

Hello everyone. First post, hope I'm adhering to the rules.

I've been reading PDF after PDF of x299 motherboard manuals and I can't find an answer to the following:

Is there a x299 motherboard that has at least one of its PCIe m.2 sockets connected straight to the CPU (I'm getting a 44 PCIe lane CPU)? And if there is, can I boot from a single, non-raided, non-Intel NVMe SSD like the Samsung 960 connected to said slot?

Thank you!!
Reply to hernan.c.martinez
9 answers Last reply
More about x299 motherboard pcie socket connected straight cpu
  1. No. Only the GPU slot connects to the CPU. The CPU only has a fixed number of pcie lanes and those are put to the pciex16 slots for the gpu.
    All the rest of the lanes come off the x299 chip.

    There is a dual m.2 slot x8 board that may work but it is not bootable.
    Reply to popatim
  2. Humm. I know there where x99 based motherboards where the m.2 PCIe slot bypassed the Chipset and connected straight to the CPU. I just want to know which of the x299 are also like that.
    Reply to hernan.c.martinez
  3. Which ones? My MSI is acting up and I might jump ship if I can find something better.
    Reply to popatim
  4. @popatim.

    Barring a catastrophic failure on their review: Look for:

    "Those setups only add up to 24 lanes each, leaving four lanes untapped. The remainder is reserved for PCIe SSDs plugged into the Deluxe's M.2 socket.
    Most motherboards' M.2 implementations are restricted to dual Gen2 lanes from the chipset. On top of that, they're bound by limited interconnect bandwidth shared with the X99's other I/O components. The Deluxe's M.2 socket bypasses those handicaps by hooking directly into the CPU."
    Reply to hernan.c.martinez
  5. I have to review my motherbd manual and see what I actually have now. TYVM!

    I'll keep checking motherbds and see if I find anything.
    Reply to popatim
  6. The Gigabyte X299 Aorus Gaming 7/9 have the M2M_32G connected directly to the CPU via 4 lanes; these lanes are shared with the 2nd PCIe slot (x4 but physically x16). Naturally, if you use that M.2 socket that PCIe slot is disabled. You can certainly boot from it with a Samsung NVMe SSD...
    Reply to quirkyquark
  7. I haven't seen any x299 mobo manual where they clearly state which m.2 socket is connected straight to the CPU, but I wonder if we can use the following instead, given what @quirkyquark said:

    - If the manual says that a given m.2 socket is shared with a PCIe slot then we can assume it's connected to the CPU
    - If the manual says that a given m.2 socket is shared with SATA ports then we can assume it's connected to the PCH/Chipset.

    Thanks :)
    Reply to hernan.c.martinez
  8. @hernan.c.martinez: that's a decent metric, but remember that most of the X299 mobos also have x1/x4 PCIE slots coming off the PCH and it's possible they (idiotically) might share one of those with an M.2 slot.

    I think another thing to look out for is whether the manual/specs say if an M.2 slot will accept only PCI-E SSDs or accepts SATA/AHCI M.2s as well.
    Reply to quirkyquark
  9. Good call quirky! I was going to add that if a sata port gets disable then its probably a Chipset m.2 slot.
    Reply to popatim
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