diff --git a/crates/coremem/src/sim/spirv/mod.rs b/crates/coremem/src/sim/spirv/mod.rs
index 950998f..0da736b 100644
--- a/crates/coremem/src/sim/spirv/mod.rs
+++ b/crates/coremem/src/sim/spirv/mod.rs
@@ -705,8 +705,8 @@ mod test {
         ) {
             use rand::{Rng as _, SeedableRng as _};
             let mut rng = rand::rngs::StdRng::seed_from_u64(seed);
-            let mut ref_state = SpirvSim::new_with_backend(size, 1e-3, CpuBackend::default());
-            let mut dut_state = SpirvSim::new_with_backend(size, 1e-3, WgpuBackend::default());
+            let mut cpu_state = SpirvSim::new_with_backend(size, 1e-3, CpuBackend::default());
+            let mut wgpu_state = SpirvSim::new_with_backend(size, 1e-3, WgpuBackend::default());
 
             for z in 0..size.z() {
                 for y in 0..size.y() {
@@ -716,17 +716,17 @@ mod test {
                             rng.gen_range(0.0..1e6),
                             rng.gen_range(0.0..1e6),
                         );
-                        ref_state.put_material(Index::new(x, y, z), AnisomorphicConductor::new(cond.cast()));
-                        dut_state.put_material(Index::new(x, y, z), AnisomorphicConductor::new(cond.cast()));
+                        cpu_state.put_material(Index::new(x, y, z), AnisomorphicConductor::new(cond.cast()));
+                        wgpu_state.put_material(Index::new(x, y, z), AnisomorphicConductor::new(cond.cast()));
                     }
                 }
             }
 
             // TODO: we should apply this on every frame?
-            ref_state.apply_stimulus(&RngStimulus::new(seed));
-            dut_state.apply_stimulus(&RngStimulus::new(seed));
+            cpu_state.apply_stimulus(&RngStimulus::new(seed));
+            wgpu_state.apply_stimulus(&RngStimulus::new(seed));
 
-            test_same_explicit(ref_state, dut_state, step_iters, steps_per_iter);
+            test_same_explicit(cpu_state, wgpu_state, step_iters, steps_per_iter);
         }
 
         #[test]
@@ -744,8 +744,8 @@ mod test {
         ) {
             use rand::{Rng as _, SeedableRng as _};
             let mut rng = rand::rngs::StdRng::seed_from_u64(seed);
-            let mut ref_state = SpirvSim::new_with_backend(size, 1e-3, CpuBackend::default());
-            let mut dut_state = SpirvSim::new_with_backend(size, 1e-3, WgpuBackend::default());
+            let mut cpu_state = SpirvSim::new_with_backend(size, 1e-3, CpuBackend::default());
+            let mut wgpu_state = SpirvSim::new_with_backend(size, 1e-3, WgpuBackend::default());
 
             for z in 0..size.z() {
                 for y in 0..size.y() {
@@ -760,21 +760,19 @@ mod test {
                         let slope = rng.gen_range(0.0..0.9*f32::mu0_inv());
                         let b_end = b_start + b_range;
                         let m_max = b_range * slope;
-                        ref_state.put_material(Index::new(x, y, z), coremem_cross::mat::MBPgram::new(
+                        let mat = coremem_cross::mat::MBPgram::new(
                             b_start.cast(), b_end.cast(), m_max.cast()
-                        ));
-                        dut_state.put_material(Index::new(x, y, z), coremem_cross::mat::MBPgram::new(
-                            b_start.cast(), b_end.cast(), m_max.cast()
-                        ));
+                        );
+                        cpu_state.put_material(Index::new(x, y, z), mat.clone());
+                        wgpu_state.put_material(Index::new(x, y, z), mat.clone());
                     }
                 }
             }
 
-            // TODO: use new (not new_e)
-            ref_state.apply_stimulus(&RngStimulus::new_e(seed));
-            dut_state.apply_stimulus(&RngStimulus::new_e(seed));
+            cpu_state.apply_stimulus(&RngStimulus::new(seed));
+            wgpu_state.apply_stimulus(&RngStimulus::new(seed));
 
-            test_same_explicit(ref_state, dut_state, step_iters, steps_per_iter);
+            test_same_explicit(cpu_state, wgpu_state, step_iters, steps_per_iter);
         }
 
         #[test]
@@ -783,22 +781,22 @@ mod test {
         }
 
         #[test]
-        fn mb_ferromagnet_100_steps_larger() {
-            test_same_mb_ferromagnet(0x1234, 10, 10, Index::new(96, 16, 8));
+        fn mb_ferromagnet_50_steps_larger() {
+            test_same_mb_ferromagnet(0x1234, 10, 5, Index::new(96, 16, 8));
         }
 
         #[test]
         fn step_multiple_with_stim() {
             let size = Index::new(4, 12, 8);
-            let mut ref_state: SpirvSim<R32, FullyGenericMaterial<R32>, CpuBackend> =
+            let mut cpu_state: SpirvSim<R32, FullyGenericMaterial<R32>, CpuBackend> =
                 SpirvSim::new(size, 1e-3);
-            let mut dut_state: SpirvSim<R32, FullyGenericMaterial<R32>, WgpuBackend> =
+            let mut wgpu_state: SpirvSim<R32, FullyGenericMaterial<R32>, WgpuBackend> =
                 SpirvSim::new(size, 1e-3);
             let stim = stim::Fields::new_e(Vec3::new(1.0e15, 2.0e15, -3.0e15).cast::<R32>());
             for _ in 0..5 {
-                ref_state.step_multiple(100, &stim);
-                dut_state.step_multiple(100, &stim);
-                assert_simstate_eq(&dut_state, &ref_state);
+                cpu_state.step_multiple(100, &stim);
+                wgpu_state.step_multiple(100, &stim);
+                assert_simstate_eq(&wgpu_state, &cpu_state);
             }
         }
     }