We’ve just finished uploading the latest versions of our XCache and eAccelerator plugins, now at version 0.6.

For those of you that missed the initial announcement, we’ve written two plugins that let WordPress communicate directly with memory-resident opcode PHP variable caches that are used in XCache and eAccelerator to boost performance and decrease I/O activity.

eAccelerator and XCache are the two most-popular open-source opcode caching engines for PHP, and we highly recommend that any and all hosts use them to improve PHP performance by several folds. In particular, we recommend XCache for best performance.

In this episode of “The Never-Ending Quest for Better Server Performance,” we follow our heroes’ journey through the dangerous and murky woods of PHP opcode caching engines, where they aren’t content with just installing an opcode caching engine, but <gasp> becoming one with it too!

Yep, you heard that right. We’ve just released two new plugins for the WordPress users out there, that take opcode caching to the next level. If you haven’t already installed an opcode caching engine like XCache (our favorite!), eAccelerator, Turck MMcache, Memcached, APC, or PHPA then you really need to do that right now before even continuing this article. Really, what were you waiting for!?

For all the Windows-bound PHP users out there, consider yourselves warned: even if you’re running the (supposedly) thread-safe PHP Win32 binary redistribution, you’re still susceptible to PHP Access Violation Errors, race problems, heap corruption, and much worse if you use the popular eAccelerator opcode-caching extension.

We did our testing with the binaries compiled by SiteBuddy using the latest versions of both PHP and eAccelerator. Almost immediately after initiating a stress test on our test servers we experienced the dreaded “PHP Access Violation” error - which brings down the entire IIS Worker Process to its heels.