System memory isn't that fast, either. Even with DDR5-8400, the fastest memory you can get right now, you're only looking at a memory transfer speed of 67.2 GB/s, barely faster than the PCI-E bus. So even if you could store that entire 70B model in RAM, you're still getting just under 1 token/sec, and that's assuming your CPU doesn't become a bottleneck.
Your best bet would likely be a laptop that has integrated system RAM with VRAM, but I don't think any of those offer enough RAM to store an entire 70B model. A 7B parameter model would work fine, but you could do those on a consumer-grade GPU anyways.
