It's just a rough estimate given that these things are fairly linear, the original 7B mistral was 15 GB and the new one is 86 GB, whereas a fully duplicated 8 * 15 GB would suggest a 120 GB size, so 86/120 = 0.71 for actual size, suggesting 29% memory savings. This of course doesn't really account for any multiple vs single file saving overhead and such, so it's likely to be a bit off.
