Every open wp-admin tab sends Heartbeat requests every 15–60 seconds. Editors with five tabs open generate steady background load that hosting support loves to blame. We measured admin-ajax traffic on three live sites, then tested the two plugins that control it.
What the measurement showed
| Site | admin-ajax requests/hour | Heartbeat share | Server CPU impact |
|---|---|---|---|
| Content blog, 2 editors | 310 | 61% | Negligible |
| Store, 8 editors + plugins | 2,900 | 44% | Noticeable at peaks |
| B2B site with page builder | 5,100 | 37% | Significant — builder saving checks |
The surprise: on the B2B site, most admin-ajax was not Heartbeat at all — the page builder polls for changes while editors work. Heartbeat control alone would have fixed 37% of a problem that was 63% something else. This is the misdiagnosis pattern from the plugin diagnostic: measure before medicating.
The plugins
- Heartbeat Control: free, one job — throttle or disable Heartbeat globally, in admin, or on post editor. Setting: 60s admin, 60s editor, disabled elsewhere. Safe; autosave moves to 60s cadence.
- Perfmatters: same controls bundled with its script unloading — if you already run it, no extra plugin.
When it matters (and when it does not)
- Matters: shared hosting CPU throttles, many concurrent editors, sites where “admin is slow” complaints correlate with Heartbeat spikes.
- Does not matter: single-editor sites on decent VPS — 310 requests/hour is nothing. Cleanup here is ritual, like revision cleanup on small sites.
If front-end speed is the actual complaint, backend chatter is a side quest — the free audit separates the two.
The admin-ajax.php API powering autosave, lock indicators, and session tracking. It pings every 15–60 seconds per open admin tab — noticeable with many editors or tabs. Mostly: autosave slows, revision locks loosen, and some plugins (page builders, WooCommerce analytics) rely on it. Throttle to 60s rather than disable fully. Heartbeat is usually blamed, but on our measurements page builders and plugins often generate most traffic. Log the requested actions before optimizing anything. No — Perfmatters includes the same heartbeat throttling settings. Heartbeat Control is the free stand-alone option.What is WordPress Heartbeat?
Is disabling Heartbeat safe?
Why is admin-ajax.php getting so many requests?
Do I need Heartbeat Control if I use Perfmatters?
