http://chanarchive.org/content/86_fit/4138960/1280996624967.jpg
If these de-syncs are so spontaneous in nature, why do they occur near the end of matches? just would like a technical answer on why this phenomenon occurs.
but these de-syncs gotta stop. do they occur often on ssf4?
I can offer a theory on this end of round desync problem.
You know how Super Tubro has variable attack damage? By that I mean the same move does not always do the same damage, it will vary seemingly randomly within what appears to be a given boundary (maybe +/-5% of the base damage). A good example is to load a save state in arcade ST and look at the amount of pixels that dissapear when you do a close stand fierce or something - it varies a little.
Now hereās what I think it has to do with end of round desyncs. We all know about rollback and roughly how the online system works. I understand the game tries to predict what happens and if it predicts wrong, it puts itself right with the next set of move/coordinate data it gets and this to us appears as rollback.
That rollback is because you have two versions of the game running on consoles miles apart. The lag, or rollback is primarily caused by the distance between the players, not so much the bandwidth as a game like ST requires very little bandwidth to run.
Now letās say we have P1 using Ryu and P2 using Ken. Ryu has plenty of health but Ken has a tad more than a fierce punch worth of health left. For reasons unknown to us, Ryu decides to end the round with a close fierce punch. On his console, the game generated the fierce punch + a bit of additional random damage, and that was just enough to kill Ken, so P1ās console thinks that the game has ended. Meanwhile due to the time it takes for data to move from one location to another (a ping of 16 means it takes 1 frame for your button input to reach the opponent), P2ās console tries to predict the attack. It predicted correctly, but it predicted the amount of random damage the move would do incorrectly meaning on P2ās screen, the close fierce didnāt do enough damage to kill him (would have left him alive with no 0 vital).
I believe this is where the desync occurs. One console thinks the round has ended and attempts to go through the motion of closing the game and going back to the lobby, but the other console which generated a random amount of damage less than the first console, still thinks the game is in play. This state of one console going back to the lobby and one being in game probably looks like an end of round ragequit to the software.
Remember that although rollback corrects (or is supposed to) mistakes in the prediction, if the ping is high, it takes longer for the correct information to reach the other console. Two players that have a ping of 160 are 10 frames apart. If we go back to the fierce punch situation, itās easy to see how the consoles could get it wrong and desync if it takes 10 frames for the correct input to reach P2ās console. P1ās console has probably long decided that the game is over and closed the connection or something, before P2 gets the data and can say, āOk, I lostā and close his connection.
Thatās how I believe it works. I didnāt develop the game so donāt take what I say as the truth, but I think Iām probably on the right lines.
This would hold true because the clocks which the random generators use probably canāt be synced. However this problem doesnāt seem to plague st ggpo at all.
-trolls suck-
that was a interesting read 
Ahhh thanks ZERO1. Thirst quenched better than gatorade.
Now if we can just get this info into the Enterpriseās computer so that the universe will know, I will sleep even better. 
Thanks again.
I donāt believe I can summarize that theory, so I reposted it. ;^)
Ok, after sleeping on this a bit, is this what happened?
i) Blitzfu has at least 10% life left. So according to the theory, one of the consoles decides that 10% is really gone ( part of the variable damage) and Sim wins - except I got a loss.
ii) It takes 9 seconds ( 5:58 to 6:07) for the console(s) to realize this - 9 seconds where neither player is moving or pressing buttons on opposite sides of the screen.
just wonderin.
well, its wrong, the game has randomizers, yes, but from 2 randomizers at a rollback, the hitting attack/grabber end has the priority, a disconnect is what happened to u, the dude knew if he dcād he wouldnt get a loss in his ranking, its the server which has to give someone a loss, in this case since u r the only one āstill playingā u get the loss added, even if u were about to win.
how long does it take to disconnect? it varies for each modem or router, the good news is u can always avoid that loss 
anytime u c the oponent connection seems to freeze, means he turned his modem off, u can do the same(unplugging the ethernet also works) n no one gets a loss since the server has no one as āstill playingā
he disconnected on purpose on 6:05, then u had about 3 secs(6:08) to disconnect as well to avoid the auto loss, from 5:58 to 6:04 he was just fucking around with u
Incorrect. The desync problem manifests in a disconnection as soon as one person āwinsā the match. From what I understand having been both the disconnector and the disconnectee, the first person to āwinā the match after the desync goes to the lobby, where nobody can start a match until the loser disconnects (or, if in ranked, just goes to the main screen). The āloserā will probably see the āwinnerā doing ārandom attacksā that donāt seem to make sense, until the winner goes to the lobby; once that happens, the screen freezes for the loser and he disconnects. In ranked, the loser is still assigned a loss, which shows up in the leaderboards. This has happened to me before on ranked, and is a pretty crappy way to receive a loss (especially if it happens from a first round desync).
It is easier to see if the desync occurs from a KO on the first round. Ex: we have Player A and Player B fighting, both with little life left, and Player A throws Player B, and they both desync on the amount of damage Player B actually took. Player A thinks heās won, so he just sort of stops playing usually. However, Player B still has life on his screen, and sees Player A just standing there, probably thinking that Player A made some mistake on whether or not he won. So then Player B KOs Player A, meanwhile Player A is starting the next round already.
Usually what happens next is described above, with the opponent seemingly doing random things, because the match is desynced. Player A is probably killing Player B wondering why he isnāt playing normally, and Player B is probably killing Player A for the same reason. Once Player A gets the 2nd KO, Player Bās screen freezes and is disconnected. This would explain the ā9 second delayā - it is actually an arbitrary delay based on how fast Player A decides to get the second KO.
I donāt know if being the room host has any bearing on what happens above.
Interesting theories, who wouldāve thought everyone in here would be getting along so nicely?
Iām with Reno - after all, heās at or near the top of my list of the most intelligent people on Xbox live.
well bad games to xbl ranked 2 more losses outta nowhere via desync. seems the de-sync rate has gone up. sigh.
That problem is usually not that prevalent when playing against anybody from the U.S. That is until you fight virtually ANYBODY from overseas or in Mexico or Canada. The desync problem (when playing against a U.S. player) doesnāt really affect me as long as the other player doesnāt pay for their internet with cash crops. In digression, bad games to me for not having played HD Remix recently.
When playing 3 ranked games against a certain player in Ireland, the games would play normally, no rage quit or anything and although I won the 3 matches, none were even counted on my Xbox live record at all and my rank was unchanged. I did not try checking to see if the same was true on streetfighter.com where you can also check the ranks. Itās better than getting a loss, but itās ridiculous nonetheless.
Bad games to el patriarch or whatever his name is, one of several Akuma players who send rage mail after losing.
āel patriarchā is an asshole. Anytime Iāll beat him, heāll send me rage mail in which he claims that I am lucky that he wasnāt trying. Or heāll occasionally type Spanish obscenities.
That douchebag?
He messaged me yesterday calling me a freak after I kept beating him all the time.
Stupid ass.
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That guy has been messaging me all night. Calling me a faggot LOL
El needs to realize that heās the guy in a droptop Sebring thinking heās the shitā¦ Stop it, El Patricia!!! Weāre strikinā back against your homo ass!!! Your novice Akuma methods have been sniffed out time and time again!!! The fact that you suck so bad with him is eventually going to make shitty Akuma players like yourself accepted to use him every match. I believe the whole community KNOWS they can fuck that shitty Akuma up and really donāt care if you use him anymore because:
YOUāRE GOING TO LOSE EVERYTIME, REGARDLESS.
GO PLAY SFIV, PUTZ.