diff --git a/interface/ger.c b/interface/ger.c
index b2f803dec..8cf1614e3 100644
--- a/interface/ger.c
+++ b/interface/ger.c
@@ -175,7 +175,7 @@ void CNAME(enum CBLAS_ORDER order,
 
 #ifdef SMPTEST
   // Threshold chosen so that speed-up is > 1 on a Xeon E5-2630
-  if(1L * m * n > 24L * GEMM_MULTITHREAD_THRESHOLD)
+  if(1L * m * n > 2048L * GEMM_MULTITHREAD_THRESHOLD)
     nthreads = num_cpu_avail(2);
   else
     nthreads = 1;
diff --git a/interface/zger.c b/interface/zger.c
index 5bcbfc09b..f7354d26d 100644
--- a/interface/zger.c
+++ b/interface/zger.c
@@ -214,7 +214,7 @@ void CNAME(enum CBLAS_ORDER order,
 
 #ifdef SMPTEST
   // Threshold chosen so that speed-up is > 1 on a Xeon E5-2630
-  if(1L * m * n > 3L * sizeof(FLOAT) * GEMM_MULTITHREAD_THRESHOLD)
+  if(1L * m * n > 36L * sizeof(FLOAT) * sizeof(FLOAT) * GEMM_MULTITHREAD_THRESHOLD)
     nthreads = num_cpu_avail(2);
   else
     nthreads = 1;