Gentoo Linux/AMD64 Frequently Asked Questions Simon Stelling Luis Medinas Gerald J. Normandin Jr. Xavier Neys This is the Gentoo Linux/AMD64 Frequently Asked Questions 4 2012-03-28 Questions
Introduction to Gentoo/AMD64 FAQ


What's the difference between AMD64 and EM64T?

Both refer to 64-bit processors from AMD (AMD64) and Intel (EM64T). AMD's 64-bit processors include the Athlon 64, Turion, Neo, Phenom, and Opteron families. Intel's 64-bit processors include the Core2, Core iX, Celeron, Xeon, and Pentium (all based on the Core2 architecture). The last few versions of the old Pentium 4 and Xeon chips also support EM64T.

The AMD line of 64-bit processors were released well ahead of Intel's offering. Therefore, for historical reasons the arch keyword for all x86-64 compatible architectures is amd64. As such, AMD64 is a generic reference to 64-bit chips, whether AMD or Intel.

What CFLAGS should I use for AMD64/EM64T?

You should use simple CFLAGS to avoid future problems with your system. Supported CFLAGS are -O2 -march=k8 -pipe for AMD systems. Intel Core2-based systems (EM64T) should use -O2 -march=core2 -pipe. If you're on an old Intel Pentium 4 that supports EM64T, then use -O2 -march=nocona -pipe.

What kernel should I use for AMD64?



Make sure you have the IA32_EMULATION option activated in the kernel.

# cd /usr/src/linux
# make menuconfig

Executable file formats / Emulations  --->
  [*] IA32 Emulation

That is a difficult question to answer. In some cases, you will experience a performance improvement, in other cases you will not. For everyday use, there is nearly no difference between 64bit and 32bit. 64bit is generally faster when it comes to floating point computing which is normally the case in multimedia applications and 3D rendering. This article (and a related article) may interest you. There's also a nice thread in our forums.

What is multilib and how can I use it?


How do I create a 32bit chroot?

Please read the 32bit chroot guide.



Also, binary files created on an x86 system most likely cannot be read by packages on an amd64 system. In particular, databases such as MySQL, innoDB, Berkeley DB, SQLite, OpenLDAP, etc. cannot simply be copied as-is. You will need to dump the database into an architecture-independent format, such as a text file, before attempting to restore it on an amd64 system.

Can I use Reiser4?

Reiser4 is not available from any kernel offered by the Gentoo Kernel project, thus the AMD64 team doesn't support it. The answer is no.

Will my binary NVIDIA/ATI drivers work?


How do I use Cool'n'Quiet/PowerNow/SpeedStep features?


Power management options --->
  [*] Run-time PM core functionality
    <*>   Processor
    <*>     Thermal Zone
  CPU Frequency scaling --->
  [*] CPU Frequency scaling
         Default CPUFreq governor (ondemand) --->
  -*-   'performance' governor
  <*>   'userspace' governor for userspace frequency scaling
  -*-   'ondemand' cpufreq policy governor
  <*>   ACPI Processor P-States driver
  <*>   AMD Opteron/Athlon64 PowerNow!
-*- CPU idle PM support

Then emerge cpufrequtils and edit /etc/conf.d/cpufrequtils with your favorite editor.

# Options when starting cpufreq (given to the 'cpufreq-set' program)
START_OPTS="--governor ondemand"

# Options when stopping cpufreq (given to the 'cpufreq-set' program)
STOP_OPTS="--governor performance"

Now you only have to run rc-update add cpufrequtils boot to make sure it is started every time you boot.

Can I get Adobe Flash working?

Yes. Just emerge adobe-flash. Be sure to read any messages displayed by the ebuild once it has been emerged.

Can I get working?

Yes. Run emerge openoffice. It may take several hours and use most of your system resources. If you don't think your machine is up to it, you can try installing the precompiled binary, openoffice-bin.





# emerge packagename


How can I help the Gentoo/AMD64 project?
How can I help?


  • Filing general bug reports
  • Testing software that does not yet have the ~amd64 keyword
  • Participating in the Arch Testers project
  • Sending patches
Other Resources
