I needed a persistent object cache while doing work on a budget hosting provider. A lot of the other file-based caching plugins were either bundled with other things I didn’t need (W3 Total Cache), or were old and broken.
On the sites I’ve tested this with, that have slow database servers, I have noticed an increase in page generation times of about 2x. On the other hand, for sites that have fast database servers it can actually increase page generation time. Whenever possible, I’d recommend using Memcached, Redis, or your other quality cache of choice.
Install like any other plugin, directly from your plugins page or manually by copying the files to the
plugins/ folder. Go to the plugin settings page at Settings->FOCUS Cache and click
Enable Object Cache.