Antminer S21 vs S19 — Which Should You Buy?

Two different generations

The S21 is more efficient; the S19 is cheaper up front. The right pick depends on your budget horizon and tariff.

When the S19 wins

Lower entry price, proven workhorse, great if power is cheap or you're starting small.

When the S21 wins

Better J/TH means lower running cost — it pays back the price premium over a long deployment.

Rule of thumb: cheap power favours older rigs; expensive power favours efficiency.