diff --git a/packages/object/src/hashgraph/index.ts b/packages/object/src/hashgraph/index.ts
index f0c3edc7b..1d0524f9f 100644
--- a/packages/object/src/hashgraph/index.ts
+++ b/packages/object/src/hashgraph/index.ts
@@ -166,16 +166,20 @@ export class HashGraph {
 
 	dfsTopologicalSortIterative(origin: Hash, subgraph: ObjectSet<Hash>): Hash[] {
 		const visited = new ObjectSet<Hash>();
-		const result: Hash[] = [];
-		const stack: Hash[] = [origin];
+		const result: Hash[] = Array(subgraph.size);
+		const stack: Hash[] = Array(subgraph.size);
 		const processing = new ObjectSet<Hash>();
+		let resultIndex = subgraph.size - 1;
+		let stackIndex = 0;
+		stack[stackIndex] = origin;
 
-		while (stack.length > 0) {
-			const node = stack[stack.length - 1];
+		while (resultIndex >= 0) {
+			const node = stack[stackIndex];
 
 			if (visited.has(node)) {
-				stack.pop();
-				result.push(node);
+				result[resultIndex] = node;
+				stackIndex--;
+				resultIndex--;
 				processing.delete(node);
 				continue;
 			}
@@ -188,13 +192,14 @@ export class HashGraph {
 				for (const neighbor of neighbors.sort()) {
 					if (processing.has(neighbor)) throw new Error("Graph contains a cycle!");
 					if (subgraph.has(neighbor) && !visited.has(neighbor)) {
-						stack.push(neighbor);
+						stackIndex++;
+						stack[stackIndex] = neighbor;
 					}
 				}
 			}
 		}
 
-		return result.reverse();
+		return result;
 	}
 
 	/* Topologically sort the vertices in the whole hashgraph or the past of a given vertex. */
diff --git a/packages/object/src/linearize/pairSemantics.ts b/packages/object/src/linearize/pairSemantics.ts
index 9c3d3066c..7e18f747e 100644
--- a/packages/object/src/linearize/pairSemantics.ts
+++ b/packages/object/src/linearize/pairSemantics.ts
@@ -58,6 +58,5 @@ export function linearizePairSemantics(
 			}
 		}
 	}
-
 	return result;
 }
diff --git a/packages/object/src/utils/objectSet.ts b/packages/object/src/utils/objectSet.ts
index cd11095b9..ce70bdf9e 100644
--- a/packages/object/src/utils/objectSet.ts
+++ b/packages/object/src/utils/objectSet.ts
@@ -1,19 +1,28 @@
 export class ObjectSet<T extends string | number | symbol> {
 	set: { [key in T]: boolean };
+	size: number;
 
 	constructor(iterable: Iterable<T> = []) {
 		this.set = {} as { [key in T]: boolean };
+		this.size = 0;
 		for (const item of iterable) {
 			this.set[item] = true;
+			this.size++;
 		}
 	}
 
 	add(item: T): void {
+		if (this.has(item)) return;
+
 		this.set[item] = true;
+		this.size++;
 	}
 
 	delete(item: T): void {
+		if (!this.has(item)) return;
+
 		delete this.set[item];
+		this.size--;
 	}
 
 	has(item: T): boolean {
diff --git a/packages/object/tests/actiontypes.test.ts b/packages/object/tests/actiontypes.test.ts
index bf798d8d7..939023b35 100644
--- a/packages/object/tests/actiontypes.test.ts
+++ b/packages/object/tests/actiontypes.test.ts
@@ -89,7 +89,6 @@ describe("Test: ActionTypes (Nop and Swap)", () => {
 		addMul.add(5);
 		drp.merge(drp2.vertices);
 		drp2.merge(drp.vertices);
-
 		addMul.mul(5);
 		addMul.add(5);
 		addMul2.add(5);
@@ -99,8 +98,11 @@ describe("Test: ActionTypes (Nop and Swap)", () => {
 		expect(addMul2.query_value()).toBe(75);
 
 		addMul2.mul(2);
+		vi.setSystemTime(new Date(Date.UTC(1998, 11, 24)));
 		addMul2.add(2);
+		vi.setSystemTime(new Date(Date.UTC(1998, 11, 25)));
 		addMul.add(3);
+		vi.setSystemTime(new Date(Date.UTC(1998, 11, 26)));
 		addMul.mul(3);
 		drp.merge(drp2.vertices);
 		drp2.merge(drp.vertices);