diff --git a/src/ipa/ipu3/algorithms/af.h b/src/ipa/ipu3/algorithms/af.h
index 13c7e0e8..108fcd18 100644
--- a/src/ipa/ipu3/algorithms/af.h
+++ b/src/ipa/ipu3/algorithms/af.h
@@ -20,7 +20,7 @@ static constexpr uint8_t kAfMinGridWidth = 16;
 static constexpr uint8_t kAfMinGridHeight = 16;
 static constexpr uint8_t kAfMaxGridWidth = 32;
 static constexpr uint8_t kAfMaxGridHeight = 24;
-static constexpr uint16_t kAfMinGridBlockWidth = 4;
+static constexpr uint16_t kAfMinGridBlockWidth = 3;
 static constexpr uint16_t kAfMinGridBlockHeight = 3;
 static constexpr uint16_t kAfMaxGridBlockWidth = 6;
 static constexpr uint16_t kAfMaxGridBlockHeight = 6;