Welcome, Guest
Username: Password: Remember me

TOPIC: PCIe lanes

PCIe lanes 2 months 4 weeks ago #15952

  • unni
  • unni's Avatar
  • Offline
  • Lurker
  • Posts: 2
  • Karma: 0
Hello. Question about PCIe lanes:

According to the specs on the (e.g.) Gigabyte X299 UD4 (link below) and other X299 Motherboards, if we use a 16 lane CPU we will only get PCIe running at x8, with either one or two graphics cards. Does this mean that the PCIe lanes get reserved for other PCIe slots, even though they aren't used?

Thanks

LINK: www.gigabyte.eu/Motherboard/X299-UD4-rev-10#sp
Last Edit: 2 months 4 weeks ago by unni.
The administrator has disabled public write access.

PCIe lanes 2 months 4 weeks ago #15953

  • JD_And_Chocolatebear
  • JD_And_Chocolatebear's Avatar
  • Offline
  • GN Staff
  • Posts: 319
  • Thank you received: 100
  • Karma: 29
I'm not quite sure what you mean by "Does this mean that the PCIe lanes get reserved for other PCIe slots, even though they aren't used?"
The administrator has disabled public write access.

PCIe lanes 2 months 4 weeks ago #15954

  • unni
  • unni's Avatar
  • Offline
  • Lurker
  • Posts: 2
  • Karma: 0
I'm not sure of what I mean either, I'm just trying to find an explanation. My point is:

If an older 16 lane CPU can run a card at x16 on other platforms, why can't this 16 lane CPU run one card at x16 on this one? I'm I getting it right from the specs? Are the specs right? Is this a property of the platform or is it defined by the MBs manufacturers?

Or am I simply not getting it right at all and a 16 lane CPU simply can't run a PCIe card at x16?

Thanks again
Last Edit: 2 months 4 weeks ago by unni.
The administrator has disabled public write access.

PCIe lanes 2 months 4 weeks ago #15955

  • i7Baby
  • i7Baby's Avatar
  • Offline
  • Moderator
  • Posts: 625
  • Thank you received: 96
  • Karma: 22
When using a 16 lane CPU (4-core):
1-Way 2-Way*
PCIEX16_1 ∨(x8) ∨(x8)
PCIEX16_2 ╳ ∨(x4)
PCIEX8 ╳ ╳
∨: Installed, ╳: Not Installed.
* Supports the CrossFire technology only.

Looks like 4 pcie lanes are reserved for storage drive applications.

See www.anandtech.com/show/11461/intel-annou...orm-and-x299-chipset

"If a user has a 16 lane CPU in place with one storage drive, the GPU slot can be x8 with the network controller and storage active, or if the GPU slot(s) is x16 or x8/x8, then the network controller and PCIe storage is disabled, unless muxes and quick switches are equipped on the motherboard to carry the signal around such that the PCIe storage moves to chipset based, or defaults to SATA only, or etc etc etc"
R7-1700 @3900/1.375V, H110iGT, ASRock x370 Taichi, GSkill 2x8GB 3200/14 @3466/14 1.38V, Samsung 250gb EVO (W10), 2TB Barracuda, 2 x R9 Nano, EVGA G2 750, Enthoo Pro, LG 34UM88. Aizo kb, M6580, HyperX Cloud
Last Edit: 2 months 4 weeks ago by i7Baby.
The administrator has disabled public write access.
The following user(s) said Thank You: unni
Moderators: 2ndPlayer, i7Baby
Time to create page: 0.097 seconds
Powered by Kunena Forum

We moderate comments on a ~24~48 hour cycle. There will be some delay after submitting a comment.

Advertisement:

  VigLink badge