diff --git a/packages/backend/src/core/CollapsedQueueService.ts b/packages/backend/src/core/CollapsedQueueService.ts
index aa21f7578f..36c2c6962d 100644
--- a/packages/backend/src/core/CollapsedQueueService.ts
+++ b/packages/backend/src/core/CollapsedQueueService.ts
@@ -60,7 +60,10 @@ export class CollapsedQueueService implements OnApplicationShutdown {
 				isNotResponding: false,
 				suspensionState: job.shouldUnsuspend ? 'none' : undefined,
 			}),
-			this.onQueueError,
+			{
+				onError: this.onQueueError,
+				concurrency: 2, // Low concurrency, this table is slow for some reason
+			},
 		);
 
 		this.updateUserQueue = new CollapsedQueue(
@@ -70,7 +73,10 @@ export class CollapsedQueueService implements OnApplicationShutdown {
 				updatedAt: new Date(Math.max(oldJob.updatedAt.getTime(), newJob.updatedAt.getTime())),
 			}),
 			(id, job) => this.usersRepository.update({ id }, { updatedAt: job.updatedAt }),
-			this.onQueueError,
+			{
+				onError: this.onQueueError,
+				concurrency: 4,
+			},
 		);
 
 		this.internalEventService.on('localUserUpdated', this.onUserUpdated);
diff --git a/packages/backend/src/misc/collapsed-queue.ts b/packages/backend/src/misc/collapsed-queue.ts
index 8b70bcc505..a2b1166faf 100644
--- a/packages/backend/src/misc/collapsed-queue.ts
+++ b/packages/backend/src/misc/collapsed-queue.ts
@@ -3,7 +3,8 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import type { TimeService, TimerHandle } from '@/global/TimeService.js';
+import { TimeService, type TimerHandle } from '@/global/TimeService.js';
+import promiseLimit from 'promise-limit';
 
 type Job<V> = {
 	value: V;
@@ -12,6 +13,7 @@ type Job<V> = {
 
 // TODO: redis使えるようにする
 export class CollapsedQueue<K, V> {
+	private readonly limiter?: ReturnType<typeof promiseLimit<void>>;
 	private jobs: Map<K, Job<V>> = new Map();
 
 	constructor(
@@ -20,8 +22,15 @@ export class CollapsedQueue<K, V> {
 		private readonly timeout: number,
 		private readonly collapse: (oldValue: V, newValue: V) => V,
 		private readonly perform: (key: K, value: V) => Promise<void | unknown>,
-		private readonly onError?: (queue: CollapsedQueue<K, V>, error: unknown) => void,
-	) {}
+		private readonly opts?: {
+			onError?: (queue: CollapsedQueue<K, V>, error: unknown) => void,
+			concurrency?: number,
+		},
+	) {
+		if (opts?.concurrency) {
+			this.limiter = promiseLimit<void>(opts.concurrency);
+		}
+	}
 
 	enqueue(key: K, value: V) {
 		if (this.jobs.has(key)) {
@@ -49,9 +58,15 @@ export class CollapsedQueue<K, V> {
 
 	private async _perform(key: K, value: V) {
 		try {
-			await this.perform(key, value);
+			if (this.limiter) {
+				await this.limiter(async () => {
+					await this.perform(key, value);
+				});
+			} else {
+				await this.perform(key, value);
+			}
 		} catch (err) {
-			this.onError?.(this, err);
+			this.opts?.onError?.(this, err);
 			throw err;
 		}
 	}