diff --git a/crates/applications/stacked_cores/src/main.rs b/crates/applications/stacked_cores/src/main.rs
index 05c7d03..f50cd6a 100644
--- a/crates/applications/stacked_cores/src/main.rs
+++ b/crates/applications/stacked_cores/src/main.rs
@@ -3906,23 +3906,6 @@ fn run_sim<const C: usize, const R: usize>(
     // each col M denotes the drive current at core M.
     let num_cycles = drive_map.len() as u32;
     let num_cores = drive_map[0].len() as u32;
-    let mut core_drivers = vec![Vec::default(); num_cores as usize];
-    for (cycle, cores) in drive_map.into_iter().enumerate() {
-        for (core, clock) in cores.into_iter().enumerate() {
-            core_drivers[core as usize].extend(clock.time_stimulus(&params, cycle as u32));
-        }
-    }
-    let stim: Vec<_> = core_drivers.into_iter()
-        .enumerate()
-        .map(|(core, time_varying)| {
-            let region = params.ctl(core as u32);
-            let area = region.cross_section();
-            let amp = 1.0 / area;
-            let v_field = CurlVectorField::new(region.clone());
-            ModulatedVectorField::new(v_field, time_varying.scaled(amp.cast::<R>()))
-        })
-        .collect();
-    assert_eq!(stim.len(), num_cores as usize);
 
 
     let ctl_mat = IsomorphicConductor::new(params.ctl_conductivity.cast::<R>());
@@ -3934,6 +3917,25 @@ fn run_sim<const C: usize, const R: usize>(
     let mut driver = Driver::new(Sim::new(
         sim_bounds(num_cores).to_index(feat_size), feat_size,
     ));
+
+    let duration = Seconds(params.clock_phase_duration * num_cycles as f32);
+    let snapshot_freq = 12800;
+    let duration_frames = duration.to_frame(driver.timestep()).round_up(snapshot_freq);
+    let prefix = format!("out/applications/stacked_cores/{}/", name);
+    let _ = std::fs::create_dir_all(&prefix);
+    driver.add_state_file(&*format!("{}state.bc", prefix), snapshot_freq);
+
+    if driver.steps_until(duration_frames) == 0 {
+        println!("sim already completed");
+        return; // all our work is done
+    }
+
+    driver.add_serializer_renderer(&*format!("{}frame-", prefix), 6400, Some(12800));
+    // driver.add_csv_renderer(&*format!("{}meas-detailed.csv", prefix), 100, None);
+    driver.add_csv_renderer(&*format!("{}meas.csv", prefix), 1600, None);
+    driver.add_csv_renderer(&*format!("{}meas-sparse.csv", prefix), 12800, None);
+    driver.set_steps_per_stimulus(200);
+
     driver.add_classical_boundary(sim_padding);
 
     //////// create the wires and toroids
@@ -4005,26 +4007,30 @@ fn run_sim<const C: usize, const R: usize>(
     }
 
 
-    let duration = Seconds(params.clock_phase_duration * num_cycles as f32);
+    //////// add the stimuli
+    let mut core_drivers = vec![Vec::default(); num_cores as usize];
+    for (cycle, cores) in drive_map.into_iter().enumerate() {
+        for (core, clock) in cores.into_iter().enumerate() {
+            core_drivers[core as usize].extend(clock.time_stimulus(&params, cycle as u32));
+        }
+    }
+    let stim: Vec<_> = core_drivers.into_iter()
+        .enumerate()
+        .map(|(core, time_varying)| {
+            let region = params.ctl(core as u32);
+            let area = region.cross_section();
+            let amp = 1.0 / area;
+            let v_field = CurlVectorField::new(region.clone());
+            ModulatedVectorField::new(v_field, time_varying.scaled(amp.cast::<R>()))
+        })
+        .collect();
+    assert_eq!(stim.len(), num_cores as usize);
 
-    // let stim = DynStimuli::from_vec(stim.map(MapIntoBoxStimulus).into_vec());
     let mut driver = driver.with_modulated_stimulus();
     for s in stim {
         driver.add_stimulus(s);
     }
 
-    let prefix = format!("out/applications/stacked_cores/{}/", name);
-    let _ = std::fs::create_dir_all(&prefix);
-    driver.add_state_file(&*format!("{}state.bc", prefix), 12800);
-    driver.add_serializer_renderer(&*format!("{}frame-", prefix), 6400, Some(12800));
-    // driver.add_csv_renderer(&*format!("{}meas-detailed.csv", prefix), 100, None);
-    driver.add_csv_renderer(&*format!("{}meas.csv", prefix), 1600, None);
-    driver.add_csv_renderer(&*format!("{}meas-sparse.csv", prefix), 12800, None);
-    driver.set_steps_per_stimulus(200);
-
-    driver.step_until(
-        duration
-            .to_frame(driver.timestep())
-            .round_up(25600)
-    );
+    driver.step_until(duration_frames);
+    println!("sim complete");
 }