Speedsters in comics are a common sight these days, but two of particular note have been Makkari from Marvel and The Flash from DC. Though Quicksilver would've probably been a much easier match-up to handle, plenty of others have looked to The Eternals over X-Men or the Age of Ultron version of Quicksilver. The speed difference is quite pronounced with those two, and Quicksilver vs. Flash has been done already.
The two speedsters of their various universes belong to two different teams: The Eternals and the Justice League. Each defends the world in their own way, with The Eternals from cosmic threats and the Justice League from dangers too large for even Superman to defeat.
Naturally, debates on which speedster is fastest were going to crop up eventually. So, we asked CHATGPT to come up with an answer of which of the two speedsters would outrace the other, and it surprisingly came up with an even-handed answer.
Chatgpt predicts who would win in a race between Marvel's Makkari and DC's Flash
The chatbot gave a pretty even-handed argument about the actual speed between the two. It's more general information than a blow-by-blow breakdown of each feat, saying where they're from and that it depends on the author and who could outspeed whom in a race.
In an unsurprising process of thought, the AI said that the results of one speedster trying to blitz past the other would heavily depend on the comic book and adaptation. Further questioning on this front revealed it didn't have any relevant data on the MCU version of Makkari.
The comic book Makkari vs. comic book Flash yielded much the same results. A very even-handed type of response. It's unsurprising given that both Flash and Makkari have existed for decades and have done feats like breaking the sound barrier, and other things.
Final thoughts
For most fans, that's obviously not going to be a satisfying answer to the question. Even when putting it into Marvel Cinematic Universe and DC Extended Universe terms, the AI bot answered the same way: it depends on their abilities and the context.
As the AI bot's last update was in September 2021 and the MCU film The Eternals came out in October 2021, it was unable to give a straight answer.
This seems to be a technological limitation, so some context is absolutely required. The Marvel Cinematic Universe version of Makkari is faster than sound, can travel from Rio to Glenfinnan in three seconds, scouts planets for The Eternals, and is faster than Captain Marvel. Comics Makkari is more serious and can go faster than light.
The DCEU Flash, on the other hand, is faster than light, faster than Zod, and has time traveled. The Flash movie, the CW TV show, The Flashpoint Paradox animated movie, and more than a few other comics have proven how quick The Flash is when he goes all out. It also depends on which Flash is being discussed.
On a more humorous note, there exists a comic entitled Quasar #17 from 1990 that depicts this very event in Marvel Comics. The Flash expy, "The Runner" was named "Buried Allen" to avoid copyright issues and won the race against Makkari and other speed-based heroes. He is then renamed FastForward.
This is one area wherein even AI isn't going to truly be able to answer the question of who's faster. This, much like the AI chatbot said, is going to have to be resolved by checking all of the different eras and abilities and comparing and contrasting them all.