Mainly GPU and memory (vram). For example, LLMs run smoothly on my MacBook with a Max chip and 64GB of RAM, but any PC with a recent high-end GPU will suffice. As for storage, SSDs are way better for performance compared to HDDs, however HDD should work.what kind of computer do you need to run it? I assume the processing power is mostly heavy for the CPU. How heavy is the LLM? Can it run smoothly on a HDD? Also what UI would you suggest for general, not specific use?
For a user interface, you might want to try LM Studio paired with Mistral-8x7B model. Check out LM Studio - Discover and run local LLMs for more details.