Ubuntu is currently officially compatible with five processor architectures - x86_64 (aka AMD64), ARM64 (aka AArch64), PowerPC64 (aka POWER), System z (aka S390X), and RISC-V. Previously supported architectures include x86, PowerPC, and SPARC64.
x86_64
This covers AMD processors with the "amd64" extension and Intel processors with the "em64t" extension. Most consumer desktops, laptops, and servers from 2006 onwards use this architecture. Examples of processors that use this architecture are:
* AMD Athlon 64 * AMD Athlon II * AMD Ryzen * AMD Opteron * Intel Pentium D * Intel Core 2 * Intel Core i3/i5/i7/i9 * Intel Core Ultra
ARM
64 bit ARM SoCs (System on Chip) from multiple SoC vendors have been enabled and certified on Ubuntu 14.04 and newer releases. Please refer to https://www.ubuntu.com/download/server/arm for download and installation instructions. A list of Ubuntu-certified ARM SoCs and Servers can be found on Ubuntu the SoC Certification (see https://certification.ubuntu.com/soc/) and Ubuntu Server Certification pages (see https://certification.ubuntu.com/server/).
POWER (OpenPOWER) Servers
As of Ubuntu 14.04 LTS, IBM's POWER8 (ppc64el) architecture and its OpenPOWER variants are fully supported. Please refer to http://wiki.ubuntu.com/ppc64el for details.
S390X (IBM Mainframe Systems)
As of Ubuntu 16.04 LTS, certain systems that utilize IBM's S390X architecture, also referred to as "System z" and "LinuxONE" are fully supported. Currently, these are: IBM z13, IBM z13s, IBM zEC12, IBM zBC12, LinuxONE Emperor and LinuxONE Rockhopper. Please refer to https://wiki.ubuntu.com/S390X for details.
x86 (legacy)
Note: support for this architecture was dropped after 19.10. 18.04 was the last version for which ISO images were produced.
This covers the vast majority of desktop and laptop PCs and small-to-medium servers from the early 90s to 2006, and netbooks as late as 2009. Computers with an x86_64 architecture could also run this version.
Examples of processors that used this architecture (but are not compatible with the x86_64 architecture) are:
* AMD K6-2 * Intel Pentium * Intel Pentium Pro * Intel Pentium II * AMD Athlon * AMD Athlon XP * Intel Pentium III * Intel Pentium 4 (some later models are x86_64) * Intel Celeron D * Intel Core Duo * Via C7
PowerPC (legacy)
Please note, that PowerPC Long Term Support ended with Ubuntu 6.06. Updates were still available from Ubuntu Ports until Ubuntu 16.04.
This covers the majority of machines with a PowerPC CPU.
Most prominent are the Power Macintoshes produced by Apple. Note that older Macs with a Motorola 680x0 processor are *not* covered here. (They have the "m68k" architecture, which isn't supported by Ubuntu but may be supported by other Linux distributions.)
The PowerPC family is quite varied though, you can find everything from Power Macintosh clones to IBM small-to-medium servers here.
This architecture also covers most bus systems that are in use with the PowerPC processor. The most notable exception is the NuBus, which was used in some Apple Macintosh models (before Apple switched over to PCI). (A Linux kernel and limited support for the NuBus can be found at http://nubus-pmac.sourceforge.net/).
Here's a list of supported models:
Manufacturer: Apple (Linux Subarchitecture: powermac-NewWorld)
- iMac Bondi Blue, 5 Flavors, Slot Loading
- iMac Summer 2000, Early 2001
- iBook, iBook SE, iBook Dual USB
- iBook2
Power Macintosh Blue and White (B&W) G3
- Power Macintosh G4 PCI, AGP, Cube
- Power Macintosh G4 Gigabit Ethernet
- Power Macintosh G4 Digital Audio, Quicksilver
PowerBook G3 FireWire Pismo (2000)
PowerBook G3 Lombard (1999)
PowerBook G4 Titanium
Manufacturer: Apple (Linux Subarchitecture: powermac-OldWorld)
- Performa 4400, 54xx, 5500
- Performa 6360, 6400, 6500
- Power Macintosh 4400, 5400
- Power Macintosh 7200, 7300, 7500, 7600
- Power Macintosh 8200, 8500, 8600
- Power Macintosh 9500, 9600
- Power Macintosh (Beige) G3 Minitower
- Power Macintosh (Beige) Desktop, All-in-One
PowerBook 2400, 3400, 3500
PowerBook G3 Wallstreet (1998)
- Twentieth Anniversary Macintosh
- Workgroup Server 7250, 7350, 8550, 9650, G3
Manufacturer: Power Computing (Linux Subarchitecture: powermac-OldWorld)
PowerBase, PowerTower / Pro, PowerWave
PowerCenter / Pro, PowerCurve
Manufacturer: UMAX (Linux Subarchitecture: powermac-OldWorld)
- C500, C600, J700, S900
Manufacturer: APS (Linux Subarchitecture: powermac-OldWorld)
- APS Tech M*Power 604e/2000
Manufacturer: Motorola (Linux Subarchitecture: powermac-OldWorld)
- Starmax 3000, 4000, 5000, 5500
- Manufacturer: Motorola (Linux Subarchitecture: prep)
Firepower, PowerStack Series E, PowerStack II
- MPC 7xx, 8xx
- MTX, MTX+
- MVME2300(SC)/24xx/26xx/27xx/36xx/46xx
- MCP(N)750
- Manufacturer: IBM (Linux Subarchitecture: prep)
- RS/6000 40P, 43P
- RS/6000 Power 830/850/860 (6070, 6050)
- RS/6000 6030, 7025, 7043
- RS/6000 p640
- RS/6000 B50, 43P-150, 44P
- Manufacturer: Amiga Power-UP Systems (Linux Subarchitecture: apus)
- A1200, A3000, A4000
This list is not exhaustive. New models are constantly being brought out, and some older models may be absent because they haven't been tested.
SPARC64 (legacy)
SPARC64 processors were supported from 6.06, 7.04, 7.10 on the server edition only. As of 8.04, SPARC is no longer commercially supported. It was maintained as an Ubuntu Port through 10.04.
Multiprocessor Machines
All of the above architectures may come in a multiprocessor flavor (often called "symmetric multiprocessing" or SMP). This is not a problem for Ubuntu: it can handle multiple processors just fine.
The installation process may choose to use just one of the CPUs, but that's no cause for alarm: you'll be given the opportunity to adapt Ubuntu to your hardware later, from this page: CompileTheKernel.