diff --git a/src/amd/vulkan/nir/radv_nir_lower_cooperative_matrix.c b/src/amd/vulkan/nir/radv_nir_lower_cooperative_matrix.c
index 7c4cfe5bc95..2e9ee078679 100644
--- a/src/amd/vulkan/nir/radv_nir_lower_cooperative_matrix.c
+++ b/src/amd/vulkan/nir/radv_nir_lower_cooperative_matrix.c
@@ -72,25 +72,25 @@ radv_nir_cmat_length(struct glsl_cmat_description desc, const lower_cmat_params
    if (params->gfx_level >= GFX12) {
       assert(desc.cols == 16 && desc.rows == 16);
       return 256 / params->wave_size;
+   } else if (desc.use != GLSL_CMAT_USE_ACCUMULATOR) {
+      return 16;
    } else {
-      return desc.use != GLSL_CMAT_USE_ACCUMULATOR
-                ? 16
-                : (desc.cols * desc.rows / params->wave_size * 32 / radv_nir_cmat_bits(desc));
+      return desc.cols * desc.rows / params->wave_size * (radv_nir_cmat_bits(desc) == 16 ? 2 : 1);
    }
 }
 
 static unsigned
 radv_nir_cmat_length_mul(struct glsl_cmat_description desc, const lower_cmat_params *params)
 {
-   if (params->gfx_level >= GFX12) {
+   if (params->gfx_level >= GFX12 || desc.use != GLSL_CMAT_USE_ACCUMULATOR) {
       return 1;
    } else {
-      /* For C matrices we have 1 VGPR per element even if the element type is
-       * < 32 bits. So with 8 fp16 elements we implement that with a f16vec16.
+      /* For  GFX11 C matrices we have 1 VGPR per element even if the element type is
+       * 16bits. So with 8 fp16 elements we implement that with a f16vec16.
        * We then use the coefficient generated by this function to figure out
        * how many elements we really have.
        */
-      return desc.use == GLSL_CMAT_USE_ACCUMULATOR ? (32 / radv_nir_cmat_bits(desc)) : 1;
+      return radv_nir_cmat_bits(desc) == 16 ? 2 : 1;
    }
 }