[pavlov]

It's not a plain 486. The SemiAccurate article[1] offers some more details:

How did Intel achieve a P5 ISA on a 486? Easy they added the handful of instructions to the old core while they ripped and replaced just about everything else. What did they add? Obviously the few new instructions on the P5 but not in the Pentium MMX generation. On top of that PAE and large page support was added along with local APIC style interrupt support. - -

The Quark designers did start out with a 486 design and promptly threw most of it out. Most of it is a new core but some bits were actually carried over. Why start with a 486 rather than a Pentium if you throw most of it out before adding in all the new ISA bits but not the architectural advances that the P5 line brought to the table? Easy, power. The 486 uses less while providing the performance Intel had targeted. On top of this more traditional C-State support that is much better than the 486 could dream of but nowhere near a modern CPU was added to the Quark core.

They also threw out the 486's front-side bus and replaced it with a modern SOC equivalent with PCI Express and ARM's "AMBA Fabric".

With this many changes, it sounds like a reasonably modern x86 machine (except for a total lack of MMX/SSE vector instructions) that should be able to run a Linux distro that targets older hardware.

[1] http://semiaccurate.com/2013/10/28/intel-talks-little-quark/

[sireat]

Just plain P5 (without MMX instructions) is not a reasonbly modern machine. 486 came out in 1989 and Pentium in 1993 so you are still looking at a 20 year old instruction set. I don't think there are many modern Linux distros that are targeted to P5 anymore.

Still, for $70 I might pick one up just to relive my youth and I am sure there will be some things you will be able to run.