diff --git a/src/gallium/drivers/radeonsi/si_pipe.h b/src/gallium/drivers/radeonsi/si_pipe.h
index 57e18f88034..e4179575b8d 100644
--- a/src/gallium/drivers/radeonsi/si_pipe.h
+++ b/src/gallium/drivers/radeonsi/si_pipe.h
@@ -787,6 +787,7 @@ struct si_streamout_target {
 
 struct si_streamout {
    enum mesa_prim output_prim;
+   uint8_t num_verts_per_prim;
    bool begin_emitted;
 
    unsigned enabled_mask;
diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 85db130d881..3e0575ac7f7 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -1594,13 +1594,15 @@ static void si_dump_shader_key(const struct si_shader *shader, FILE *f)
    if ((stage == MESA_SHADER_GEOMETRY || stage == MESA_SHADER_TESS_EVAL ||
         stage == MESA_SHADER_VERTEX) &&
        !key->ge.as_es && !key->ge.as_ls) {
-      fprintf(f, "  opt.kill_outputs = 0x%" PRIx64 "\n", key->ge.opt.kill_outputs);
-      fprintf(f, "  opt.kill_pointsize = 0x%x\n", key->ge.opt.kill_pointsize);
-      fprintf(f, "  opt.kill_layer = 0x%x\n", key->ge.opt.kill_layer);
-      fprintf(f, "  opt.kill_clip_distances = 0x%x\n", key->ge.opt.kill_clip_distances);
-      fprintf(f, "  opt.ngg_culling = 0x%x\n", key->ge.opt.ngg_culling);
-      fprintf(f, "  opt.remove_streamout = 0x%x\n", key->ge.opt.remove_streamout);
       fprintf(f, "  mono.remove_streamout = 0x%x\n", key->ge.mono.remove_streamout);
+      fprintf(f, "  opt.kill_outputs = 0x%" PRIx64 "\n", key->ge.opt.kill_outputs);
+      fprintf(f, "  opt.kill_clip_distances = 0x%x\n", key->ge.opt.kill_clip_distances);
+      fprintf(f, "  opt.kill_pointsize = %u\n", key->ge.opt.kill_pointsize);
+      fprintf(f, "  opt.kill_layer = %u\n", key->ge.opt.kill_layer);
+      fprintf(f, "  opt.remove_streamout = %u\n", key->ge.opt.remove_streamout);
+      fprintf(f, "  opt.ngg_culling = 0x%x\n", key->ge.opt.ngg_culling);
+      fprintf(f, "  opt.ngg_vs_streamout_num_verts_per_prim = %u\n",
+              key->ge.opt.ngg_vs_streamout_num_verts_per_prim);
    }
 
    if (stage <= MESA_SHADER_GEOMETRY)
diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
index 13144b606cb..bb5a5d5f2ff 100644
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -780,6 +780,12 @@ struct si_shader_key_ge {
       /* For NGG VS and TES. */
       unsigned ngg_culling : 11; /* SI_NGG_CULL_* */
 
+      /* If NGG VS streamout knows the number of vertices per primitive at compile time,
+       * it can put stores for all vertices in the same VMEM clause, instead of storing
+       * vertices for the 2nd and 3rd vertex conditionally because the primitive type is
+       * unknown.
+       */
+      unsigned ngg_vs_streamout_num_verts_per_prim : 2;
 
       /* For shaders where monolithic variants have better code.
        *
diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.cpp b/src/gallium/drivers/radeonsi/si_state_shaders.cpp
index 46b7b5dbee3..78798a47f24 100644
--- a/src/gallium/drivers/radeonsi/si_state_shaders.cpp
+++ b/src/gallium/drivers/radeonsi/si_state_shaders.cpp
@@ -1369,6 +1369,15 @@ unsigned si_get_input_prim(const struct si_shader_selector *gs, const union si_s
    if (key->ge.opt.ngg_culling & SI_NGG_CULL_VS_LINES)
       return MESA_PRIM_LINES;
 
+   switch (key->ge.opt.ngg_vs_streamout_num_verts_per_prim) {
+   case 3:
+      return MESA_PRIM_TRIANGLES;
+   case 2:
+      return MESA_PRIM_LINES;
+   case 1:
+      return MESA_PRIM_POINTS;
+   }
+
    if (return_unknown)
       return MESA_PRIM_UNKNOWN;
    else
@@ -2525,8 +2534,21 @@ static void si_get_vs_key_outputs(struct si_context *sctx, struct si_shader_sele
    key->ge.opt.ngg_culling = sctx->ngg_culling;
    key->ge.mono.u.vs_export_prim_id = vs->stage != MESA_SHADER_GEOMETRY &&
                                       sctx->shader.ps.cso && sctx->shader.ps.cso->info.uses_primid;
-   key->ge.opt.remove_streamout = vs->info.enabled_streamout_buffer_mask &&
-                                  !sctx->streamout.enabled_mask;
+
+   if (vs->info.enabled_streamout_buffer_mask) {
+      if (sctx->streamout.enabled_mask) {
+         key->ge.opt.remove_streamout = 0;
+         key->ge.opt.ngg_vs_streamout_num_verts_per_prim =
+            sctx->gfx_level >= GFX11 ? sctx->streamout.num_verts_per_prim : 0;
+      } else {
+         key->ge.opt.remove_streamout = 1;
+         key->ge.opt.ngg_vs_streamout_num_verts_per_prim = 0;
+      }
+   } else {
+      key->ge.opt.remove_streamout = 0;
+      key->ge.opt.ngg_vs_streamout_num_verts_per_prim = 0;
+   }
+
    if (sctx->gfx_level >= GFX12)
       key->ge.mono.remove_streamout = key->ge.opt.remove_streamout;
 }
@@ -2538,6 +2560,7 @@ static void si_clear_vs_key_outputs(struct si_context *sctx, struct si_shader_se
    key->ge.opt.kill_outputs = 0;
    key->ge.opt.remove_streamout = 0;
    key->ge.opt.ngg_culling = 0;
+   key->ge.opt.ngg_vs_streamout_num_verts_per_prim = 0;
    key->ge.mono.u.vs_export_prim_id = 0;
    key->ge.mono.remove_streamout = 0;
 }
diff --git a/src/gallium/drivers/radeonsi/si_state_streamout.c b/src/gallium/drivers/radeonsi/si_state_streamout.c
index f0d6144b90c..b1ed4f11f7c 100644
--- a/src/gallium/drivers/radeonsi/si_state_streamout.c
+++ b/src/gallium/drivers/radeonsi/si_state_streamout.c
@@ -218,6 +218,8 @@ static void si_set_streamout_targets(struct pipe_context *ctx, unsigned num_targ
       sctx->do_update_shaders = true; /* to keep/remove streamout shader code as an optimization */
 
    sctx->streamout.output_prim = output_prim;
+   sctx->streamout.num_verts_per_prim = output_prim == MESA_PRIM_UNKNOWN ?
+                                           0 : mesa_vertices_per_prim(output_prim);
    sctx->streamout.num_targets = num_targets;
    sctx->streamout.enabled_mask = enabled_mask;
    sctx->streamout.append_bitmask = append_bitmask;