I throwed a stack of diamonds and EscEsc till both the hotbar and floor have diamonds, and exit the game, reenter, focus on another window,till the game opened, exit and regoin, and 3 stacks of diamonds were in the hotbar. I tried for several times, but only a few worked. No quad duplicating happened.

This would be faster then the initial frame glitch but I do not think it would beat the alt-f4 glitch. It could however save important seconds in some of the really refined runs. I may do a comparison later this week if I have time.

I have never succeeded in Alt+F4 glitch. Does it rely on launcher(MCLauncherBN) or os(Win7)?

it relies on the slowness of the game:

you pick up items, then forcequit (alt+f4). The game saves your inventory faster than the surrounding tiles so it will save the items in your inventory, but not save that they were picked up, thus leaving them on the ground

note: If your PC is too fast, it will have saved that the items were picked up from the floor.

There might be other reasons why this happens, but thats what I tell people in marathons ^^

i though it didnt work if it was too slow... I have a gaming Computer that i do my speedruns on, however I have tried the alt f4 glich on my laptop and I had about 25% success rate. frame works on it tho

My computer is from the beginning not for playing games. Bought in 2014, the whole with screen costs $300. When I Alt+F4, there seems to be a delay. Does that lead to the failure?

My laptop is like that, I belive it is to do with the speed of closing the game. I will have to do some testing

I backuped the save and tried again. This time I got a quad dup. Not sure if there's possibility that dup forever

5x dup reached. The save is uploaded http://filebin.ca/3I9PvAJRfUha/InfDup184.rar

With WR(here I mean I may backup the whole folder) I can now make x10 dup in 0.5s+throw and x20 in 1s+throw. Dup continues if http://bombch.us/B6ZT 's clock doesn't increase when loading the world and +1gt when saving, but it usually increase for 1gt when loading and 0 when exit(so it doesn't continue) or add a lot when entering(not good either) Entering increase 0 and leaving increase lot is also acceptable, but slow

I can confirm this can be continued infinitely, but you have to get a slightly specific time, I reckon this would be faster than the usual dup strat when duplicating a lot of items. the mods may want to note this.

If duping while walking, what number of dup per time is better?

for cases that you cut trees from the beginning, will it be faster to cut one and make triple to quad dup?