If you want to use the very useful caching plugin wp-cache-2, you need to be careful: it is not compatible with the PHPAccelerator. Unfortunately, you cannot use both together, only one of the two works. Quite annoying, because they address different elements - the plugin caches the output, the accelerator caches the precompiled PHP. Therefore, the accelerator would also help the cache system, since the cache system is written in PHP ...
Anyway, I have activated the plugin on the WordPress blogs I manage. Especially the Metaeule could benefit from this in the long run. The caching is currently set to 20 minutes, so that changes in the database do not hang around for too long before everyone can see them. Let's see what oddities occur during operation.
One thing I expected not to work properly anymore is the Plugin Popularity Contest - this counts how often a post has been called up. This happens much less frequently due to the caching and therefore the numbers are no longer meaningful. Ratings based on comments and trackbacks are of course still possible, but the page views are useless. A pity actually, but in return I get much lower server load and much higher delivery rates: with activated wp-cache I have a load of just under 4 with 20 competing massive accesses and shovel just under 50 requests per second. Without wp-cache I have a load of over 9 and only just manage 5 requests per second.
So with wp-cache-2 only half the load and ten times the performance. For that I gladly sacrifice the Popularity Contest.
A second plugin that I noticed: Search Hilight (standard plugin from WordPress) doesn't work. Logically - it colors search terms that are determined from the referrer of a search engine. And referrers do not go into the cache signature. A pity, it was a visually nice gimmick. But on the other hand not really that important.