Found the numbers, apparently its -
The OP-1 can store the following:
Max Synth Sampler patches = 42
Max Synth Synthesis patches = 100
Max Drum Patches = 42
That kind of confuses me tho as my memory was full recently before factory reset and update to new OS, but I feel like i havn't saved more than approx 60 user synth/sample patches. Maybe my memory just sucks? Or maybe there were more factory presets than I thought?
The new presets are way better but id still much prefer that space for my own patches, especially on a machine with so little memory space for slots...