diff --git a/tests/Makefile b/tests/Makefile
index 88a5d763..d0d798fc 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -200,7 +200,7 @@ zstreamtest-dll : $(ZSTDDIR)/common/xxhash.c  # xxh symbols not exposed from dll
 zstreamtest-dll : $(ZSTREAM_LOCAL_FILES)
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(filter %.c,$^) $(LDFLAGS) -o $@$(EXT)
 
-paramgrill : DEBUGFLAGS = -DNDEBUG  # turn off assert() for speed measurements
+paramgrill : DEBUGFLAGS =  # turn off assert() by default for speed measurements
 paramgrill : $(ZSTD_FILES) $(PRGDIR)/bench.c $(PRGDIR)/datagen.c paramgrill.c
 	$(CC) $(FLAGS) $^ -lm -o $@$(EXT)
 
diff --git a/tests/paramgrill.c b/tests/paramgrill.c
index 9d769596..0568626a 100644
--- a/tests/paramgrill.c
+++ b/tests/paramgrill.c
@@ -1544,6 +1544,7 @@ static int allBench(BMK_benchResult_t* resultPtr,
     U64 loopDurationC = 0, loopDurationD = 0;
     double uncertaintyConstantC = 3., uncertaintyConstantD = 3.;
     double winnerRS;
+
     /* initial benchmarking, gives exact ratio and memory, warms up future runs */
     CBENCHMARK(1, benchres, tmp, BMK_both, 1);
 
@@ -1568,6 +1569,9 @@ static int allBench(BMK_benchResult_t* resultPtr,
         return WORSE_RESULT;
     }
 
+    assert(loopDurationC >= TIMELOOP_NANOSEC / 10);
+    assert(loopDurationD >= TIMELOOP_NANOSEC / 10);
+
     /* second run, if first run is too short, gives approximate cSpeed + dSpeed */
     CBENCHMARK(loopDurationC < TIMELOOP_NANOSEC / 10, benchres, tmp, BMK_compressOnly, 1);
     CBENCHMARK(loopDurationD < TIMELOOP_NANOSEC / 10, benchres, tmp, BMK_decodeOnly,   1);