diff --git a/AsmGen/Program.cs b/AsmGen/Program.cs
index 2839d25..a4b3e75 100644
--- a/AsmGen/Program.cs
+++ b/AsmGen/Program.cs
@@ -20,8 +20,8 @@ static void Main(string[] args)
             tests.Add(new RobTest(12, 800, 1, initialDependentBranch: false));
 
             // avx-512
-            tests.Add(new Stq512Test(16, 128, 1, differentLines: true));
-            tests.Add(new Stq512Test(16, 128, 1, differentLines: false));
+            tests.Add(new Stq512Test(16, 300, 1, differentLines: true));
+            tests.Add(new Stq512Test(16, 300, 1, differentLines: false));
             tests.Add(new MaskRfTest(32, 256, 1));
 
             tests.Add(new ZeroRobTest(12, 800, 1, initialDependentBranch: false));
@@ -29,7 +29,7 @@ static void Main(string[] args)
             tests.Add(new FpRfTest(60, 800, 1, initialDependentBranch: false));;
             tests.Add(new FlagRfTest(8, 100, 1, initialDependentBranch: false));
             tests.Add(new LdqTest(80, 250, 1, initialDependentBranch: false));
-            tests.Add(new StqTest(4, 200, 1, initialDependentBranch: false));
+            tests.Add(new StqTest(4, 300, 1, initialDependentBranch: false));
             tests.Add(new MixIntVec128RfTest(4, 600, 1, initialDependentBranch: false));
             tests.Add(new MixIntRfDepBranchTest(4, 100, 1, 2));
             tests.Add(new MixIntRfDepBranchTest(4, 100, 1, 4));
@@ -84,9 +84,10 @@ static void Main(string[] args)
             //tests.Add(new FaddNsq(20, 115, 1, 115));
             tests.Add(new Vec512RfTest(20, 500, 1));
             tests.Add(new MixVec512Vec256RfTest(20, 500, 1));
-            tests.Add(new MixVec512Vec256BlockRfTest(200, 400, 1, 240));
-            tests.Add(new MixVec512Vec256BlockRfTest(200, 400, 1, 144));
-            tests.Add(new MixVec512Vec256BlockRfTest(200, 400, 1, 120));
+            tests.Add(new MixVec512Vec256BlockRfTest(200, 500, 1, 240));
+            tests.Add(new MixVec512Vec256BlockRfTest(200, 500, 1, 144));
+            tests.Add(new MixVec512Vec256BlockRfTest(200, 500, 1, 120));
+            tests.Add(new MixVec512Vec256BlockRfTest(200, 500, 1, 60));
             tests.Add(new MmxRfTest(20, 200, 1));
 
             List<Task> tasks = new List<Task>();
diff --git a/AsmGen/tests/MixVec512Vec256BlockRfTest.cs b/AsmGen/tests/MixVec512Vec256BlockRfTest.cs
index 9a98b84..0e6f2fa 100644
--- a/AsmGen/tests/MixVec512Vec256BlockRfTest.cs
+++ b/AsmGen/tests/MixVec512Vec256BlockRfTest.cs
@@ -46,14 +46,14 @@ public override void GenerateAsm(StringBuilder sb, IUarchTest.ISA isa)
                 for (int i = 0; i < nTiny; i++)
                 {
                     int regNum = ((i & 1) == 0) ? i & 0x1F : (i + 1) & 0x1F;
-                    instrsList.Add($"  vaddps %ymm2, %ymm{regNum}, %ymm{regNum}");
+                    instrsList.Add($"  vxorps %ymm2, %ymm{regNum}, %ymm{regNum}");
                 }
 
                 for (int i = nTiny; i < this.Counts[this.Counts.Length - 1];i++)
                 {
                     int regNum = ((i & 1) == 0) ? i: (i + 1);
                     regNum = (regNum + 1) & 0x1F;
-                    instrsList.Add($"  vaddps %zmm1, %zmm{regNum}, %zmm{regNum}");
+                    instrsList.Add($"  vxorps %zmm1, %zmm{regNum}, %zmm{regNum}");
                 }
 
                 string[] unrolledAdds = instrsList.ToArray();
diff --git a/AsmGen/tests/ReturnStackTest.cs b/AsmGen/tests/ReturnStackTest.cs
index 2a7f99a..ed44adb 100644
--- a/AsmGen/tests/ReturnStackTest.cs
+++ b/AsmGen/tests/ReturnStackTest.cs
@@ -69,6 +69,7 @@ public void GenerateX86GccAsm(StringBuilder sb)
                 {
                     string funcName = GetFunctionName(callDepth, callIdx);
                     sb.AppendLine($".global {funcName}");
+                    sb.AppendLine(".align 64"); // https://github.com/clamchowder/Microbenchmarks/issues/14
                     sb.AppendLine($"{funcName}:");
                     if (callIdx < callDepth - 1)
                     {