This is a thread that's been posted and asked numerous times - you can see the responses and discussion in several old and locked threads, including

454 human probability (locked) - https:/​/​www.​speedrun.​com/​smb1/​thread/​mu9qx
Is the legendary time of 4:54 possible? (locked) - https:/​/​www.​speedrun.​com/​smb1/​thread/​e8srz

the overall SoB extends past the 4:54 barrier but some of the framerules are pretty hard to save in a full run. we might see a 454 someday though by some overly dedicated runner

4:54.998 is technically possible but you’d need a perfect 8-4, 8-1fpg, happy lee’S 4-2, and 8-2 plant despawn

4-2 has not been done by a human
Perfect 8-4 isn’t realistically possible but I think taven could or gtace, nfitsi, and Kosmic can get close
And according to bismuth 8-1 fpg is 1/1000 chance

Technically it is..

This has already been discussed in far greater detail on the forums then it ever needed to be. I will repost when I said 2 months ago.
Is 4:54 possible? Yes
Will it happen? Probably not, but maybe, and maybe is all we can possibly say right now.
Will it happen any time soon? No.
Nothing has changed, and nothing will change with the knowledge we currently have.

Human SoB is 4:54, but as TheGreatestRoman said, it would be really hard. Even though all the tricks needed (4-2 top clip, 8-1 fpg, a really good 8-4) have already been made by a human, I really doubt it will happen soon.

Basically, it’s almost as hard as a perfect Mile Tyson fight.

@EmoadNomadEmoadNomad That is inaccurate
You do not need every single framerule, you only need to add 8-1 FPG and TAS 8-2 (or TAS 4-2, but that's probably not happening over TAS 8-2), and you only need to get an 8-C 8-4 (3 frames slower than current WR), not a "perfect" 8-4 that sounds like 8-7 8-4 IL WR (14 frames faster than required 8-4 speed)
From what you said, that sounds like tying the No L+R RTA TAS (4:54.26)

also 8-1 is not 1/1000 just so you know

I'm not even that experienced at 8-1 FPG yet
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@luck_ecks_dee fair enough I don’t run the game so I was just going off from what I’ve learnt. Also congrats on 4:56

@luck_ecks_dee fair enough I don’t run the game so I was just going off from what I’ve learnt. Also congrats on 4:56

@Lul_ecks_deeLul_ecks_dee fair enough I don’t run the game so I was just going off from what I’ve learnt. Also congrats on 4:56

Will 4:54 ever happen?

The answer is maybe. It requires saving 2 frame rules as I think 4-2 frame rule and a TAS-level 8-4 are both very unlikely.

The only way I see realistically see it happening is by saving both 8-1 and 8-2 frame rules in a run, and a run which nearly matches Kosmic's 8-4. Unless of course something new is found. If the perfect plant despawn can be found, then it will be more likely that 4:54 could happen.

As it stands, technically it's possible for 4:54 to occur, but super unlikely. 8-1 and 8-2 have both been done in full under normal conditions, and Kosmic's WR proves that everything else can be strung together well enough to reach under 4:55.

As time goes on, and consistency/methods improve it will become more and more likely for 4:54, and even now it's possible. Will it eventually happen? Maybe.

@EmoadNomadEmoadNomad Ok I see, now you and other people know
and thanks for congrats thicc obi