diff --git a/storage_controller/src/service.rs b/storage_controller/src/service.rs
index d3a53066c9..ae7e8d3d7d 100644
--- a/storage_controller/src/service.rs
+++ b/storage_controller/src/service.rs
@@ -4745,7 +4745,7 @@ impl Service {
                     // them in an optimization
                     const DOWNLOAD_FRESHNESS_THRESHOLD: u64 = 10 * 1024 * 1024 * 1024;
 
-                    if progress.bytes_total == 0
+                    if progress.heatmap_mtime.is_none()
                         || progress.bytes_total < DOWNLOAD_FRESHNESS_THRESHOLD
                             && progress.bytes_downloaded != progress.bytes_total
                         || progress.bytes_total - progress.bytes_downloaded
diff --git a/test_runner/performance/test_storage_controller_scale.py b/test_runner/performance/test_storage_controller_scale.py
index 17dc96dabe..632d465c3f 100644
--- a/test_runner/performance/test_storage_controller_scale.py
+++ b/test_runner/performance/test_storage_controller_scale.py
@@ -102,6 +102,9 @@ def test_storage_controller_many_tenants(
                 tenant_id,
                 shard_count,
                 stripe_size,
+                # Upload heatmaps fast, so that secondary downloads happen promptly, enabling
+                # the controller's optimization migrations to proceed promptly.
+                tenant_config={"heatmap_period": "10s"},
                 placement_policy={"Attached": 1},
             )
             futs.append(f)