diff --git a/source/compare_neon64.cc b/source/compare_neon64.cc
index 34fa3e494..0a4d52393 100644
--- a/source/compare_neon64.cc
+++ b/source/compare_neon64.cc
@@ -89,25 +89,30 @@ uint32_t SumSquareError_NEON(const uint8_t* src_a,
 uint32_t SumSquareError_NEON_DotProd(const uint8_t* src_a,
                                      const uint8_t* src_b,
                                      int count) {
+  // count is guaranteed to be a multiple of 32.
   uint32_t sse;
   asm volatile(
-      "movi        v2.16b, #0                    \n"
+      "movi        v4.4s, #0                     \n"
+      "movi        v5.4s, #0                     \n"
 
       "1:                                        \n"
-      "ld1         {v0.16b}, [%0], #16           \n"
-      "ld1         {v1.16b}, [%1], #16           \n"
-      "subs        %w2, %w2, #16                 \n"
+      "ldp         q0, q2, [%0], #32             \n"
+      "ldp         q1, q3, [%1], #32             \n"
+      "subs        %w2, %w2, #32                 \n"
       "uabd        v0.16b, v0.16b, v1.16b        \n"
+      "uabd        v1.16b, v2.16b, v3.16b        \n"
       "prfm        pldl1keep, [%0, 448]          \n"  // prefetch 7 lines ahead
-      "udot        v2.4s, v0.16b, v0.16b         \n"
+      "udot        v4.4s, v0.16b, v0.16b         \n"
+      "udot        v5.4s, v1.16b, v1.16b         \n"
       "prfm        pldl1keep, [%1, 448]          \n"
       "b.gt        1b                            \n"
 
-      "addv        s0, v2.4s                     \n"
+      "add         v0.4s, v4.4s, v5.4s           \n"
+      "addv        s0, v0.4s                     \n"
       "fmov        %w3, s0                       \n"
       : "+r"(src_a), "+r"(src_b), "+r"(count), "=r"(sse)
       :
-      : "memory", "cc", "v0", "v1", "v2");
+      : "memory", "cc", "v0", "v1", "v2", "v3", "v4", "v5");
   return sse;
 }