Reducing draw calls affecting the performance but not in a positive way

[bhushan6]

So I have scene with 6 same 3d models, each 3d model as 44 meshes within it and also I am adding few planes and sprites within that model in r3f, so whole scene has almost like 300 draw calls because i was not using instanced mesh of r3f but still i was getting 60fps on my laptop even after deploying it. But I wanted to reduce the draw calls, obviously because I was not getting that good performance on mobile devices(around 30fps on mobiles). So I merged the geometries of model and instead of looping I used instanced mesh and reduced the draw calls from 300 to 56 but now my app is running at 35fps on my laptop that is also in production. Which is weird, right? Because less draw calls should give better performance. Can anyone which tell me what I might be doing wrong?

[drcmda]

Post a small Codesandbox. It might be materials, if it has to switch programs you essentially get draw calls back, or something else but it's impossible to guess. Normally, yes, merging will reduce draw calls and make rendering faster.