Linux developers want to remove i486 and i586 Pentium CPU support to unburden kernel developers
The i486 series launched in 1989, and the i586 series debuted in 1993.
Linux is renowned for supporting incredibly ancient hardware, but there are limits to even what Linux developers can support. Phoronix reports that Linux developers are finally proposing removing support for ancient i486 and early i586 (Pentium) CPUs to unburden developers.
Linux kernel developer Ingo Molnar proposed in an RFC patch thread to remove support for these ancient 32-bit processors due to the few people running these chips combined with the latest Linux kernels. Compatibility has allegedly reached a point where supporting these chips is causing more headaches in the codebase than it's worth.
Molnar also stated that Linus Torvalds has similar feelings and desires to "...leave i486 support behind." Specifically, ending i486 and early Pentium support will allegedly remove 14,104 lines of code inside 80 files in the Linux kernel. Removing support would bump up the minimum kernel support level to include TSC and CX8 hardware support.
Linux developers have considered removing i486 support as far back as 2022, but there now appears to be mounting pressure to execute those wishes. For reference, Linux dropped support for the i386 series in 2012, marking 13 years since the last time the Linux kernel discontinued support for a deprecated CPU series.
The i486 series is an ancient Intel CPU lineup that launched back in 1989, representing Intel's fourth generation of binary-compatible CPUs. The i486 introduced several key technologies, such as a large on-chip cache and an integrated floating-point unit, components that are used in almost every single modern CPU. Depending on the model, i486 chips took advantage of 1000nm down to 600nm process nodes, with clock speeds ranging from around 20 MHz to 100 MHz. Production of the last i486 chips was discontinued in 2007.
The i586 series, also known as Intel's first Pentium-branded processor lineup, succeeded the i486 series. The original Pentium, introduced in 1993, brought along improvements from the i486 series, including a dual-integer pipeline design and a more advanced floating-point unit. The first-generation Pentium (or P5) was built on an 800nm process with clock speeds ranging from 60 MHz to 66 MHz, depending on the model.
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Aaron Klotz is a contributing writer for Tom’s Hardware, covering news related to computer hardware such as CPUs, and graphics cards.
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Grobe ReplyProduction of the last i486 chips was discontinued in 2007.
That long? It had to be a marked for this somewhere for the production going on for that long time. -
Alvar "Miles" Udell ReplyGrobe said:That long? It had to be a marked for this somewhere for the production going on for that long time.
Embedded systems. -
LabRat 891 Reply
Only issue my tiny PoV can think of, would be the ancient infrastructure still in place (esp. outside of US).Alvar Miles Udell said:Embedded systems.
AFAIK, there are still a lot of industrial control systems using various forms of i486 and Pentium.
That said, they might already be 'frozen in time' on the software-side.
I'll be truly concerned when talks of dropping i686 support, start becoming more-common. -
mlindefar Ahem, my dx4 ran 133 MHz so the 20-100mhz span is offReply
(And i newer heard of a 486 slower than 25, but maybe embedded)
... And it clocked at 166, and ran circles around the first pentium -
kluge Reply
I've got a 486sx 16/20mhz machine in my collection here. It always was used at 20mhz, unless you had some "old" software (games) that ran too fast, then you'd hit the Turbo button and it dropped to 16.mlindefar said:Ahem, my dx4 ran 133 MHz so the 20-100mhz span is off
(And i newer heard of a 486 slower than 25, but maybe embedded)
... And it clocked at 166, and ran circles around the first pentium
I *think* I have a 20/25mhz box around here somewheres too... -
willpage Reply
Pentium MMX probablyvern72 said:What would be the minimum supported CPU after that? Pentium Pro? -
EduApps Reply
I would be surprised if there ARE i486 embedded systems being updated right now in 2025Alvar Miles Udell said:Embedded systems. -
LabRat 891 Reply
Not every country is as fast-moving (technologically) as the US, EU, etc.EduApps said:I would be surprised if there ARE i486 embedded systems being updated right now in 2025
Outside the 'western world', I'd imagine a lot of industrial control equipment, etc. is still utilizing 80s and 90s technology. -
EduApps Reply
If we're talking about prices, there are Celerons cheaper and faster than a i486.LabRat 891 said:Not every country is as fast-moving (technologically) as the US, EU, etc.
https://www.amazon.com/dp/B01CTW5ELQ/ref=mp_s_a_1_4
I also have a STM32 microcontroller which is as strong as the i486.