Program takes roughly three times longer to run than it should

Ok, so I made a simple program in fusion 360, and it says machining time is 3:30 approcximately. When I actually run the program it takes more than ten minutes to complete
The maximum axis speed is limited to 1500 mm/minute while the program specifies 2000 mm/minute. However that does not account for most of the difference. I will try to post the program and link to the fusion file in the comments.

a360.co/3f5AAfZ

there is the link to the fusion file. the stepconf files are sort of locked in the other computer there, idk if they would be any use anyway.

The specified machining time does not account for G0 moves and the time it takes for the Z axis to go up and down, so on a slow machine as yours, it will take longer than the estimate.

I thought of that and tried putting in the setting to not use g0 moves, but instead only use high feedrate moves, at the same 2000 mm per minute. It makes essentially no difference.

I'm pretty sure fusion does take into account z axis move time, it would be a pretty serious flaw if it does not, although I have not tested it

In any case none of those things could account for a factor of three difference. The machine must be moving more slowly than it thinks it is, which is a problem I must resolve as the feed rate etc has to be reasonably accurate when cutting steel etc.

Ok so I realized that even though the maximum rate was set to 1500 mm per minute, the velocity display said 790 mm per minute.

I assumed it was due to the max pulse rate. The max speed displayed by Linux CNC should reflect the actual max speed but whatever.

So I changed the encoder step count per revolution from 2048 to 512, assuming it would then be able to move four times as fast, if the pulse rate is the limiting factor.

Now it moves at 1425 mm per minute according to the velocity display.

Ok.

I will keep working on it.

Ok so I went back to stepconf and updated the max speed on each axis from 25 mm to 100 mm per second. The max speed indicated in the display on the sliders for jog speed and max velocity is 6000 mm per minute, so that must be where they are derived from. The actual max velocity is 3190 or something, per axis. So problem basically solved although it's pretty messy business. There should be better diagnostics available really...