So i have superior drummer and its great except my pc struggles to run it. When i play along recording live midi it always stalls.

I dont want to type in the midi because i want it to sound more human. On Reaper there is no default drum midi sounds so i dont know how i can record these midi drums.
try using a sampler plugin that doesn't run a crapload of it's own DSP (i.e. most drum plugs that aren't superior drummer) that's some class A bad programming there, ther's no way something as simple as a sampler should be so resource intensive.

Also, try buying more RAM.
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