I recently upgraded a couple Mk3 Prusas with the new Mk3.5 kit with Input Shaper and I wanted to do a speed test so I threw in a couple other printers for comparison.

From left to right: Ender 3 V2, Prusa Mk3s+, Prusa Mk3S upgraded to Mk3.5, Prusa Mk3S+ upgraded to Mk3.5 and Bambu P1S. All the printers are in default condition and have no aftermarket upgrades.

I made a custom box from this Printables file, https://www.printables.com/model/7312..., and sliced it with all the same settings for each printer using the default profiles in Prusa Slicer for the Ender 3 and the Prusas and Bambu studio for the P1S.

My main goal for this test was to check how the 2 printers I just upgraded to Mk3.5 performed against the unmodified Prusa Mk3S+ and the Bambu P1S. I threw the Ender in for fun because it was just sitting in the corner collecting dust.

Results:
From slowest to fastest it was the Ender 3 V2 at 11hr 23min, the Prusa Mk3S+ at 8hr 11min, the 2 recently upgraded Prusa Mk3.5's at 4hr1min and the Bambu P1S at 3hr45min. The first print on the Bambu started to peel off the bed so it was stopped and restarted.

The Ender 3 had the best print quality but that’s not much of a surprise because slower speeds usually produce better results and the glue stick on the bed kept it from peeling up. More importantly, the print quality was essentially the same between the unmodified Mk3S+ and the newly upgraded Mk3.5s.

I've checked some other designs and didn't see the same 50% reduction in print time between the stock Mk3S+ and the Mk3.5's but so far it usually seems at least 25-30% faster.

For the price of the upgrade it seems worth the money to me if you already have a Mk3 printer but I wouldn't go buy a new one to just do the upgrade. You could just buy a new Bambu P1S or A1 for cheaper that have faster print speeds.

Mk3.5 upgrade: https://www.prusa3d.com/product/origi...