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ASPM Settings in Asus BIOS

Level 8

My new Asus z790 board has various settings for ASPM currently disabled by default. Is there any advantage in enabling them for a desktop PC only have a NVidia GOPU in the main PCIe slot:

Here are the settings currently disabled:

PCI Express Native Power Management

Allows you to enhance the power saving feature of PCI Express and perform ASPM operations in the operating system. Configuration options: [Disabled] [Enabled]

The following item appears only when PCI Express Native Power Management is set to [Enabled].

Native ASPM
Set this item to [Enabled] for OS Controlled ASPM, or set this item to [Disabled] for BIOS controlled ASPM. Configuration options: [Auto] [Enabled] [Disabled]

PCH - PCI Express

DMI Link ASPM Control

Allows you to control the Active State Power Management of the DMI Link. Configuration options: [Disabled] [L1] [Auto]

Allows you to select the ASPM state for energy-saving conditions. Configuration options: [Disabled] [L1] [Auto]

L1 Substates
Allows you to select the PCI Express L1 Substates settings. Configuration options: [Disabled] [L1.1] [L1.1 & L1.2]

SA - PCI Express


Allows you to set the DMI ASPM Support. Configuration options: [Disabled] [Auto] [ASPM L0s] [ASPM L1] [ASPM L0sL1]

Allows you to set the DMI Gen3 ASPM Support. Configuration options: [Disabled] [Auto] [ASPM L0s] [ASPM L1] [ASPM L0sL1]

Allows you to control the ASPM support for the PEG 0. This has no effect if PEG is not the currently active device. Configuration options: [Disabled] [L0s] [L1] [L0sL1]

PCI Express Clock Gating
Allows you to enable or disable PCI Express Clock Gating for each root port. Configuration options: [Disabled] [Enabled]


Level 10

I used to disable all and it was bad so following the recent trends with latency on Nvidia drivers which I made to be arround 400 which is aceptable but driver still needs work.

I enable the Native settings so Windows controls them, you can then disable them per energy power plan.


The PCH - PCIExpress

This are responsible for the communication of the PCH aka "southbridge" to the pciexpress, I guess only maters if you have a nvme that uses the PCH depends on motherboards but for example the Z790 apex the 2nd nvme is on the PCH where the data gets multiplexed with the DMI bus which connects the PCH to the CPU, PCH also controls ethernet/wifi/usb3/usb3.1(not sure)/sata, I would disable this ones on a desktop the power savings arent that worth

the SA - PCIexpress

Is the 20 Lanes direct from the CPU to the PCI express bus that connect both the 2 PCIexpress ports 16(lanes) and the main NVME slot(4 lanes) and for better latency with the graphics card and main NVME I stronly recomend this settintgs to be disabled including the Clock Gating.


Level 9

Sorry I know this thread is a little old now but I'm curious if the information above still holds true.

PCI Express Native Power Management in bios Enabled 

Native ASPM Enabled to pass the handling to the OS

And the rest disabled?

Trying to find information in what PCI Express Clock Gating actually does is almost impossible.

This is for a desktop with a z790-e gaming mobo btw