diff --git a/libtransmission/inout.c b/libtransmission/inout.c
index 3317b4195..8ee6f2557 100644
--- a/libtransmission/inout.c
+++ b/libtransmission/inout.c
@@ -308,6 +308,8 @@ recalculateHash( tr_torrent       * tor,
     SHA1_Init( &sha );
     bytesLeft = tr_torPieceCountBytes( tor, pieceIndex );
 
+    tr_ioPrefetch( tor, pieceIndex, offset, bytesLeft );
+
     while( bytesLeft )
     {
         const int len = MIN( bytesLeft, buflen );