diff --git a/src/Simulation/Native/src/external/fused.hpp b/src/Simulation/Native/src/external/fused.hpp
index 2b170461e41..fdde401785f 100644
--- a/src/Simulation/Native/src/external/fused.hpp
+++ b/src/Simulation/Native/src/external/fused.hpp
@@ -145,7 +145,10 @@ class Fused
             if (envNT == NULL) { // If the user didn't force the number of threads, make an intelligent guess
                 int nMaxThrds = std::thread::hardware_concurrency();        // Logical HW threads
                 if (nMaxThrds > 4) nMaxThrds/= 2;                           // Assume we have hyperthreading (no consistent/concise way to do this)
-                if (wfnCapacity < 1u << 20) {
+                if (wfnCapacity < 1ul << 14)      nMaxThrds = 1;
+                else if (wfnCapacity < 1ul << 16) nMaxThrds = 2;
+                else if (wfnCapacity < 1ul << 20)
+                {
                     if (nMaxThrds > 8) nMaxThrds = 8;                       // Small problem, never use too many
                     else if (nMaxThrds > 3) nMaxThrds = 3;                  // Small problem on a small machine
                 }