Local LLMs on Refurb M4 Max vs new M5 Max

Hoping the community can guide me on this one. I'm on the fence about the following purchase:

Refurbished 16-inch MacBook Pro Apple M4 Max Chip with 16‑Core CPU and 40‑Core GPU, 64gb ram, 1Tb Drv for $3,479.00

vs

The new 16-inch MacBook Pro Apple M5 Max Chip with 18‑core CPU, 40‑core GPU, 64gb ram, 2Tb Drv for $4,599.00

I'm drawn to the refurb due to price.

I'm going to be using it for work (data scientist & intelligence analyst), but I also want to run models like Gemma 4 31B at Q8, and Qwen3.6-27B Q8. Mainly data work (derivation and data element extraction etc). I've been using local models for a while, but hitting my head on the resource ceiling of 24gb shared ram.

There's a huge price difference ($1,120). Just wanted to check myself. Is the difference in pre-fill worth it for the m5, and any other enhancements? The reviews seem to indicate the M4 Max can run hot.

Thanks in advance.

Editing:

New info which may help shape advice:

M5 better Prefill

Memory Bandwidth:

- M4 Max 40-core GPU: 546 GB/s

- M5 Max 40-core GPU: 614 GB/s

=> 12.5% bandwidth increase.