diff --git a/libs/ardour/test/fpu_test.cc b/libs/ardour/test/fpu_test.cc
index b0b89621ee..dd4b865e76 100644
--- a/libs/ardour/test/fpu_test.cc
+++ b/libs/ardour/test/fpu_test.cc
@@ -37,7 +37,7 @@ FPUTest::tearDown ()
 }
 
 void
-FPUTest::run (size_t align_max)
+FPUTest::run (size_t align_max, float const max_diff)
 {
 	apply_gain_to_buffer (_test1, _size, 1.33);
 	default_apply_gain_to_buffer (_comp1, _size, 1.33);
@@ -58,16 +58,16 @@ FPUTest::run (size_t align_max)
 
 			CPPUNIT_ASSERT_MESSAGE (string_compose ("Compute peak not aligned off: %1 cnt: %2", off, cnt), fabsf (pk_test - pk_comp) < 1e-6);
 
-			/* mix buffers w/gain */
-			mix_buffers_with_gain (&_test1[off], &_test2[off], cnt, 0.45);
-			default_mix_buffers_with_gain (&_comp1[off], &_comp2[off], cnt, 0.45);
-			compare (string_compose ("Mix Buffers w/gain not aligned off: %1 cnt: %2", off, cnt), cnt);
-
 			/* mix buffers w/o gain */
 			mix_buffers_no_gain (&_test1[off], &_test2[off], cnt);
 			default_mix_buffers_no_gain (&_comp1[off], &_comp2[off], cnt);
 			compare (string_compose ("Mix Buffers no gain not aligned off: %1 cnt: %2", off, cnt), cnt);
 
+			/* mix buffers w/gain */
+			mix_buffers_with_gain (&_test1[off], &_test2[off], cnt, 0.45);
+			default_mix_buffers_with_gain (&_comp1[off], &_comp2[off], cnt, 0.45);
+			compare (string_compose ("Mix Buffers w/gain not aligned off: %1 cnt: %2", off, cnt), cnt, max_diff);
+
 			/* copy vector */
 			copy_vector (&_test1[off], &_test2[off], cnt);
 			default_copy_vector (&_comp1[off], &_comp2[off], cnt);
@@ -86,11 +86,11 @@ FPUTest::run (size_t align_max)
 }
 
 void
-FPUTest::compare (std::string msg, size_t cnt)
+FPUTest::compare (std::string msg, size_t cnt, float max_diff)
 {
 	size_t err = 0;
 	for (size_t i = 0; i < cnt; ++i) {
-		if (_test1[i] != _comp1[i]) {
+		if (fabsf (_test1[i] - _comp1[i]) > max_diff) {
 			++err;
 		}
 	}
@@ -123,7 +123,7 @@ FPUTest::avxFmaTest ()
 	mix_buffers_no_gain   = x86_sse_avx_mix_buffers_no_gain;
 	copy_vector           = x86_sse_avx_copy_vector;
 
-	run (align_max);
+	run (align_max, FLT_EPSILON);
 }
 
 void
diff --git a/libs/ardour/test/fpu_test.h b/libs/ardour/test/fpu_test.h
index d66673322e..552a69126e 100644
--- a/libs/ardour/test/fpu_test.h
+++ b/libs/ardour/test/fpu_test.h
@@ -36,8 +36,8 @@ public:
 #endif
 
 private:
-	void run (size_t);
-	void compare (std::string, size_t);
+	void run (size_t, float const max_diff = 0);
+	void compare (std::string, size_t, float const max_diff = 0);
 
 	ARDOUR::compute_peak_t          compute_peak;
 	ARDOUR::find_peaks_t            find_peaks;