diff --git a/nexus/src/db/datastore.rs b/nexus/src/db/datastore.rs
index aa1a0d221cd..d3602366f35 100644
--- a/nexus/src/db/datastore.rs
+++ b/nexus/src/db/datastore.rs
@@ -1999,7 +1999,7 @@ impl DataStore {
             .select(NetworkInterface::as_select());
 
         // This returns the state of the associated instance.
-        let stopped_instance_query = db::schema::instance::dsl::instance
+        let instance_query = db::schema::instance::dsl::instance
             .filter(db::schema::instance::dsl::id.eq(instance_id))
             .filter(db::schema::instance::dsl::time_deleted.is_null())
             .select(Instance::as_select());
@@ -2025,10 +2025,8 @@ impl DataStore {
         let pool = self.pool_authorized(opctx).await?;
         if make_primary {
             pool.transaction(move |conn| {
-                let instance_state = stopped_instance_query
-                    .get_result(conn)?
-                    .runtime_state
-                    .state;
+                let instance_state =
+                    instance_query.get_result(conn)?.runtime_state.state;
                 if instance_state != stopped {
                     return Err(TxnError::CustomError(
                         NetworkInterfaceUpdateError::InstanceNotStopped,
@@ -2065,10 +2063,8 @@ impl DataStore {
             // we're only hitting a single row. Note that we still need to
             // verify the instance is stopped.
             pool.transaction(move |conn| {
-                let instance_state = stopped_instance_query
-                    .get_result(conn)?
-                    .runtime_state
-                    .state;
+                let instance_state =
+                    instance_query.get_result(conn)?.runtime_state.state;
                 if instance_state != stopped {
                     return Err(TxnError::CustomError(
                         NetworkInterfaceUpdateError::InstanceNotStopped,
diff --git a/nexus/tests/integration_tests/instances.rs b/nexus/tests/integration_tests/instances.rs
index 77dec0b33eb..1bf0015cd2b 100644
--- a/nexus/tests/integration_tests/instances.rs
+++ b/nexus/tests/integration_tests/instances.rs
@@ -566,7 +566,7 @@ async fn test_instance_create_saga_removes_instance_database_record(
             description: String::from("instance to test saga unwind"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("inst"),
         user_data: vec![],
         network_interfaces: interface_params.clone(),
@@ -588,7 +588,7 @@ async fn test_instance_create_saga_removes_instance_database_record(
             description: String::from("instance to test saga unwind 2"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("inst2"),
         user_data: vec![],
         network_interfaces: interface_params,
@@ -674,7 +674,7 @@ async fn test_instance_with_single_explicit_ip_address(
             description: String::from("instance to test multiple nics"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nic-test"),
         user_data: vec![],
         network_interfaces: interface_params,
@@ -791,7 +791,7 @@ async fn test_instance_with_new_custom_network_interfaces(
             description: String::from("instance to test multiple nics"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nic-test"),
         user_data: vec![],
         network_interfaces: interface_params,
@@ -905,7 +905,7 @@ async fn test_instance_create_delete_network_interface(
             description: String::from("instance to test attaching new nic"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nic-test"),
         user_data: vec![],
         network_interfaces: params::InstanceNetworkInterfaceAttachment::None,
@@ -1155,7 +1155,7 @@ async fn test_instance_update_network_interfaces(
             description: String::from("instance to test updatin nics"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nic-test"),
         user_data: vec![],
         network_interfaces: params::InstanceNetworkInterfaceAttachment::None,
@@ -1224,7 +1224,7 @@ async fn test_instance_update_network_interfaces(
         instance_post(client, url_instance.as_str(), InstanceOp::Start).await;
     instance_simulate(nexus, &instance.identity.id).await;
 
-    // We'll the interface's name and description
+    // We'll change the interface's name and description
     let new_name = Name::try_from(String::from("new-if0")).unwrap();
     let new_description = String::from("new description");
     let updates = params::NetworkInterfaceUpdate {
@@ -1279,22 +1279,28 @@ async fn test_instance_update_network_interfaces(
     // description, and modification time.
     assert_eq!(updated_primary_iface.identity.name, new_name);
     assert_eq!(updated_primary_iface.identity.description, new_description);
-    assert!(
-        primary_iface.identity.time_modified
-            < updated_primary_iface.identity.time_modified
-    );
-
-    // Nothing else about the primary interface should have changed
-    assert_eq!(
-        primary_iface.identity.time_created,
-        updated_primary_iface.identity.time_created
-    );
     assert!(updated_primary_iface.primary);
-    assert_eq!(primary_iface.ip, updated_primary_iface.ip);
-    assert_eq!(primary_iface.mac, updated_primary_iface.mac);
-    assert_eq!(primary_iface.subnet_id, updated_primary_iface.subnet_id);
-    assert_eq!(primary_iface.vpc_id, updated_primary_iface.vpc_id);
-    assert_eq!(primary_iface.instance_id, updated_primary_iface.instance_id);
+
+    // Helper to check that most attributes are unchanged when updating an
+    // interface, and that the modification time for the new is later than the
+    // old.
+    let verify_unchanged_attributes =
+        |original_iface: &NetworkInterface, new_iface: &NetworkInterface| {
+            assert_eq!(
+                original_iface.identity.time_created,
+                new_iface.identity.time_created
+            );
+            assert!(
+                original_iface.identity.time_modified
+                    < new_iface.identity.time_modified
+            );
+            assert_eq!(original_iface.ip, new_iface.ip);
+            assert_eq!(original_iface.mac, new_iface.mac);
+            assert_eq!(original_iface.subnet_id, new_iface.subnet_id);
+            assert_eq!(original_iface.vpc_id, new_iface.vpc_id);
+            assert_eq!(original_iface.instance_id, new_iface.instance_id);
+        };
+    verify_unchanged_attributes(&primary_iface, &updated_primary_iface);
 
     // Try with the same request again, but this time only changing
     // `make_primary`. This should have no effect.
@@ -1323,10 +1329,6 @@ async fn test_instance_update_network_interfaces(
     .unwrap();
 
     // Everything should still be the same, except the modification time.
-    assert!(
-        updated_primary_iface.identity.time_modified
-            < updated_primary_iface1.identity.time_modified
-    );
     assert_eq!(
         updated_primary_iface.identity.name,
         updated_primary_iface1.identity.name
@@ -1335,21 +1337,10 @@ async fn test_instance_update_network_interfaces(
         updated_primary_iface.identity.description,
         updated_primary_iface1.identity.description
     );
-    assert_eq!(
-        updated_primary_iface.identity.time_created,
-        updated_primary_iface1.identity.time_created
-    );
-    assert!(updated_primary_iface1.primary);
-    assert_eq!(updated_primary_iface.ip, updated_primary_iface1.ip);
-    assert_eq!(updated_primary_iface.mac, updated_primary_iface1.mac);
-    assert_eq!(
-        updated_primary_iface.subnet_id,
-        updated_primary_iface1.subnet_id
-    );
-    assert_eq!(updated_primary_iface.vpc_id, updated_primary_iface1.vpc_id);
-    assert_eq!(
-        updated_primary_iface.instance_id,
-        updated_primary_iface1.instance_id
+    assert_eq!(updated_primary_iface.primary, updated_primary_iface1.primary);
+    verify_unchanged_attributes(
+        &updated_primary_iface,
+        &updated_primary_iface1,
     );
 
     // Add a secondary interface to the instance. We'll use this to check
@@ -1436,10 +1427,6 @@ async fn test_instance_update_network_interfaces(
 
     // It should now be the primary and have an updated modification time
     assert!(new_primary_iface.primary, "Failed to set the new primary");
-    assert!(
-        new_primary_iface.identity.time_modified
-            > secondary_iface.identity.time_modified
-    );
 
     // Nothing else about the new primary should have changed
     assert_eq!(new_primary_iface.identity.name, secondary_iface.identity.name);
@@ -1447,16 +1434,7 @@ async fn test_instance_update_network_interfaces(
         new_primary_iface.identity.description,
         secondary_iface.identity.description
     );
-    assert_eq!(new_primary_iface.identity.id, secondary_iface.identity.id);
-    assert_eq!(
-        new_primary_iface.identity.time_created,
-        secondary_iface.identity.time_created
-    );
-    assert_eq!(new_primary_iface.subnet_id, secondary_iface.subnet_id);
-    assert_eq!(new_primary_iface.vpc_id, secondary_iface.vpc_id);
-    assert_eq!(new_primary_iface.instance_id, secondary_iface.instance_id);
-    assert_eq!(new_primary_iface.mac, secondary_iface.mac);
-    assert_eq!(new_primary_iface.ip, secondary_iface.ip);
+    verify_unchanged_attributes(&secondary_iface, &new_primary_iface);
 
     // Get the newly-made secondary interface to test
     let new_secondary_iface = NexusRequest::object_get(
@@ -1481,12 +1459,6 @@ async fn test_instance_update_network_interfaces(
         "The old primary interface should now be a seconary"
     );
 
-    // The modification time should have changed
-    assert!(
-        new_secondary_iface.identity.time_modified
-            > updated_primary_iface.identity.time_modified
-    );
-
     // Nothing else about the old primary should have changed
     assert_eq!(
         new_secondary_iface.identity.name,
@@ -1496,22 +1468,7 @@ async fn test_instance_update_network_interfaces(
         new_secondary_iface.identity.description,
         updated_primary_iface.identity.description
     );
-    assert_eq!(
-        new_secondary_iface.identity.id,
-        updated_primary_iface.identity.id
-    );
-    assert_eq!(
-        new_secondary_iface.identity.time_created,
-        updated_primary_iface.identity.time_created
-    );
-    assert_eq!(new_secondary_iface.subnet_id, updated_primary_iface.subnet_id);
-    assert_eq!(new_secondary_iface.vpc_id, updated_primary_iface.vpc_id);
-    assert_eq!(
-        new_secondary_iface.instance_id,
-        updated_primary_iface.instance_id
-    );
-    assert_eq!(new_secondary_iface.mac, updated_primary_iface.mac);
-    assert_eq!(new_secondary_iface.ip, updated_primary_iface.ip);
+    verify_unchanged_attributes(&updated_primary_iface, &new_secondary_iface);
 }
 
 /// This test specifically creates two NICs, the second of which will fail the
@@ -1564,7 +1521,7 @@ async fn test_instance_with_multiple_nics_unwinds_completely(
             description: String::from("instance to test multiple bad nics"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nic-test"),
         user_data: vec![],
         network_interfaces: interface_params,
@@ -1638,7 +1595,7 @@ async fn test_attach_one_disk_to_instance(cptestctx: &ControlPlaneTestContext) {
             description: String::from("probably serving data"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nfs"),
         user_data: vec![],
         network_interfaces: params::InstanceNetworkInterfaceAttachment::Default,
@@ -1734,7 +1691,7 @@ async fn test_attach_eight_disks_to_instance(
             description: String::from("probably serving data"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nfs"),
         user_data: vec![],
         network_interfaces: params::InstanceNetworkInterfaceAttachment::Default,
@@ -1840,7 +1797,7 @@ async fn test_cannot_attach_nine_disks_to_instance(
             description: String::from("probably serving data"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nfs"),
         user_data: vec![],
         network_interfaces: params::InstanceNetworkInterfaceAttachment::Default,
@@ -1967,7 +1924,7 @@ async fn test_cannot_attach_faulted_disks(cptestctx: &ControlPlaneTestContext) {
             description: String::from("probably serving data"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nfs"),
         user_data: vec![],
         network_interfaces: params::InstanceNetworkInterfaceAttachment::Default,
@@ -2079,7 +2036,7 @@ async fn test_disks_detached_when_instance_destroyed(
             description: String::from("probably serving data"),
         },
         ncpus: InstanceCpuCount::try_from(2).unwrap(),
-        memory: ByteCount::from_mebibytes_u32(4),
+        memory: ByteCount::from_gibibytes_u32(4),
         hostname: String::from("nfs"),
         user_data: vec![],
         network_interfaces: params::InstanceNetworkInterfaceAttachment::Default,