diff --git a/ggml/src/ggml-metal.metal b/ggml/src/ggml-metal.metal
index 156466b5..6553f465 100644
--- a/ggml/src/ggml-metal.metal
+++ b/ggml/src/ggml-metal.metal
@@ -1701,7 +1701,7 @@ void kernel_mul_mv_bf16_impl(
 
     device const uint16_t * x = (device const uint16_t *) (src0 + offset0);
 
-    typedef union { uint32_t u; float f; } aux_t;
+    typedef union { uint32_t u[4]; float f[4]; } aux_t;
     aux_t aux;
 
     for (int row = 0; row < N_MV_T_T; ++row) {
@@ -1713,9 +1713,12 @@ void kernel_mul_mv_bf16_impl(
         device const T1 * y = (device const T1 *) (src1 + r1*nb11 + im*nb12);
 
         float sumf = 0;
-        for (int i = tiisg; i < ne00; i += 32) {
-            aux.u = x[i] << 16;
-            sumf += aux.f * (float) y[i];
+        for (int i = tiisg; i < ne00/4; i += 32) {
+            aux.u[0] = x[4*i+0] << 16;
+            aux.u[1] = x[4*i+1] << 16;
+            aux.u[2] = x[4*i+2] << 16;
+            aux.u[3] = x[4*i+3] << 16;
+            sumf += aux.f[0] * (float)y[4*i+0] + aux.f[1] * (float)y[4*i+1] + aux.f[2] * (float)y[4*i+2] + aux.f[3] * (float)y[4*i+3];
         }
 
         float all_sum = simd_sum(sumf);