Prefer Discrete GPU

This is a CGo package. Unfortunately there is no way to enable this behaviour without CGo as of Go 1.14

For laptops with multiple GPUs, its likely that applications won't launch using the discrete GPU on Windows, but rather the integrated GPU. This can lead to real-time applications like games under-performing by default, which is not the ideal user experience.

This library exports global variables for NVIDIA and AMD drivers so that they use high performance graphics rendering settings.

Install

go get https://github.com/silbinarywolf/preferdiscretegpu

Requirements

• Golang 1.12+

How to use

Just import the package for side-effects. This will have no additional behaviour on non-Windows systems.

package main

import (
	"fmt"

	_ "github.com/silbinarywolf/preferdiscretegpu"
)

func main() {
	// your code here
}

How to test if this package is working

1. Open up the Windows Command Line (not Powershell) and run the following:

NOTE: if you have have an older or newer version of Visual Studio installed, vcvarsall.bat will be in a different folder

call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat"

2. Build the test application that consumes this library

go build -v -o testapp.exe ./testapp

3. Run dumpbin on it:

dumpbin /exports testapp.exe

4. It should give you an output mentioning the NVIDIA/AMD constants, like so:

Microsoft (R) COFF/PE Dumper Version 14.00.24213.1
Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file testapp.exe

File Type: EXECUTABLE IMAGE

  Section contains the following exports for a.out.exe

    00000000 characteristics
    5F153BFB time date stamp Mon Jul 20 16:38:51 2020
        0.00 version
           1 ordinal base
           2 number of functions
           2 number of names

    ordinal hint RVA      name

          1    0 000B6C00 AmdPowerXpressRequestHighPerformance
          2    1 000B6C04 NvOptimusEnablement

  Summary

        1000 .CRT
       30000 .bss
       15000 .data
        1000 .debug_abbrev
        1000 .debug_aranges
       14000 .debug_frame
        1000 .debug_gdb_scripts
       82000 .debug_info
       35000 .debug_line
       88000 .debug_loc
        9000 .debug_pubnames
        E000 .debug_pubtypes
       30000 .debug_ranges
        1000 .debug_str
        1000 .edata
        1000 .idata
        1000 .pdata
       C7000 .rdata
        A000 .reloc
       A1000 .text
        1000 .tls
        1000 .xdata

Credits

• Hakan Guleryuz for documenting how they were able to export the NVIDIA/AMD variables in Golang and for giving information
• SFML Contributors for inspiring how this feature should be consumed (ie. opt-in imported package)