diff --git a/src/search.cpp b/src/search.cpp
index 9eeafbda..3dfd5d6d 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -801,13 +801,12 @@ namespace {
     }
 
     // Step 10. Internal iterative deepening (skipped when in check)
-    if (    depth >= (PvNode ? 5 * ONE_PLY : 8 * ONE_PLY)
+    if (    depth >= 6 * ONE_PLY
         && !ttMove
         && (PvNode || ss->staticEval + 256 >= beta))
     {
-        Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
         ss->skipEarlyPruning = true;
-        search<NT>(pos, ss, alpha, beta, d, cutNode);
+        search<NT>(pos, ss, alpha, beta, 3 * depth / 4 - 2 * ONE_PLY, cutNode);
         ss->skipEarlyPruning = false;
 
         tte = TT.probe(posKey, ttHit);