It'll work on either and it's open source https://github.com/openai/whisper.

There's also a cpp whisper implementation (not openai) which is prob more optimised for running on a CPU. Bit more finicky to set up though, you need to download the models you want to use then build it, etc. Instructions are straight forward though.

https://github.com/ggml-org/whisper.cpp

nostr:nprofile1qqs0w2xeumnsfq6cuuynpaw2vjcfwacdnzwvmp59flnp3mdfez3czpspremhxue69uhkummnw3ez6ur4vgh8wetvd3hhyer9wghxuet59uq3samnwvaz7tmwdaehgu3wd3hhqupwwdhkx6tpdshslw6x5e had a good wrte up on Whisper https://blog.lopp.net/openai-whisper-transcription-testing/