Sparrow is good. Are you referring to the initial mix or remixes?

Initial mix should be basically instant, and will break 100% of deterministic links.

Remixes can take time as remixers are chosen at random. Note that remixing is not necessary to gain privacy, as additional mixes that you don’t participate in also increase your forward looking anonset.

Learn more here: https://medium.com/samourai-wallet/diving-head-first-into-whirlpool-anonymity-sets-4156a54b0bc7