diff --git a/src/backend/vector/ifma/edwards.rs b/src/backend/vector/ifma/edwards.rs
index 429f3a7..beefc71 100644
--- a/src/backend/vector/ifma/edwards.rs
+++ b/src/backend/vector/ifma/edwards.rs
@@ -71,14 +71,14 @@ impl Identity for ExtendedPoint {
 
 impl ExtendedPoint {
     pub fn double(&self) -> ExtendedPoint {
-        // Set tmp0 = (X1 Y1 X1 Y1)
-        let mut tmp0 = self.0.shuffle(Shuffle::ABAB);
+        // (Y1 X1 T1 Z1) -- uses vpshufd (1c latency @ 1/c)
+        let mut tmp0 = self.0.shuffle(Shuffle::BADC);
 
-        // Set tmp1 = (Y1 X1 Y1 X1)
-        let mut tmp1 = tmp0.shuffle(Shuffle::BADC);
+        // (X1+Y1 X1+Y1 X1+Y1 X1+Y1) -- can use vpinserti128 
+        let mut tmp1 = (self.0 + tmp0).shuffle(Shuffle::ABAB);
 
-        // Set tmp0 = (X1 Y1 Z1 X1+Y1)
-        tmp0 = self.0.blend(&(tmp0 + tmp1), Lanes::D);
+        // (X1 Y1 Z1 X1+Y1)
+        tmp0 = self.0.blend(&tmp1, Lanes::D);
 
         tmp1 = F51x4Reduced::from(tmp0).square();
         // Now tmp1 = (S1 S2 S3 S4)