Not by just a bit, but it was a difference between 10MB/s and 100MB/s.
/dev/random, on linux used to stall waiting for entropy from sources of randomness like network jitter, mouse movement, keyboard typing. /dev/urandom has always been fast on Linux.
Today, linux /dev/random mainly uses an RNG after initial seeding. The BSDs always did this. On my laptop, I get over 500MB/s (kernel 6.12) .
IIRC, on modern linux kernels, /dev/urandom is now just an alias to /dev/random for backward compatibility.
Both Linux and BSD use a CSPRNG to satisfy /dev/{urandom,random} and getrandom, and, for future-secrecy/compromise-protection continually update their entropy pools with hashed high-entropy events (there's ~essentially no practical cryptographic reason a "seeded" CSPRNG ever needs to be rekeyed, but there are practical systems security reasons to do it).
Related, I stumbled down a rabbit hole of PRNGs last year when I discovered [0] that my Mac was way faster at generating UUIDs than my Linux server, even taking architecture and clock speed into account. Turns out glibc didn’t get arc4random until 2.36, and the version of Debian I had at the time didn’t have 2.36. In contrast, since MacOS is BSD-based, it’s had it for quite some time.
[0]: https://gist.github.com/stephanGarland/f6b7a13585c0caf9eb64b...
For all I know BSD could be doing 31*last or something similar.
The algorithm is also free to change.
But that's also why the rng stuff was so much faster. There was a long period of time where the Linux dev in charge of randomness believed a lot of voodoo instead of actual security practices, and chose nonsense slow systems instead of well-researched fast ones. Linux has finally moved into the modern era, but there was a long period where the randomness features were far inferior to systems built by people with a security background.
(I was involved, somewhat peripherally, in OpenBSD security during the era of the big OpenBSD Security Audit).
Ultimately, they suffer from a lack of developer resources.
Which is a shame because it's a wonderfully integrated system (as opposed to the tattered quilt that is every Linux distro). But I suspect it's the project leadership that keeps more people away.
/s