XCache is described as 'fast, stable PHP opcode cacher that has been tested and is now running on production servers under high load. It is tested on Linux and FreeBSD and supported under Windows, for thread-safe and non-thread-safe versions of PHP' and is an app in the Development category. There are five alternatives to XCache for Linux, Online / Web-based, Mac, Windows and Java. The best alternative is memcached, which is both free and Open Source. Other great apps like XCache are Apache Ignite (Free, Open Source), HyperDex (Free, Open Source), eAccelerator (Free, Open Source) and Alternative PHP Cache (Free, Open Source).
Apache Ignite In-Memory Data Fabric is a high-performance, integrated and distributed in-memory platform for computing and transacting on large-scale data sets in real-time, orders of magnitude faster than possible with traditional disk-based or flash technologies.
eAccelerator is a free open-source PHP accelerator & optimizer. It increases the performance of PHP scripts by caching them in their compiled state, so that the overhead of compiling is almost completely eliminated. It also optimizes scripts to speed up their execution.