Many research groups have been working on producing PC-driven projection based VR displays. Some of these have focused on reducing the cost of such displays, while others seek to develop high-end systems using more widely available computers, to ease application development.
The NAVE was designed as a multi-screen display with many of the features of a CAVE, but at a lower cost. It is a 3 screen, PC-driven, passive stereo display. It sacrifices the CAVE features of a floor projection and tracking. Four PCs are used to generate and synchronize the graphics, which are displayed using linear polarization via VREX 2210 projectors.
Belleman et al. describe the construction of a single-screen active stereo system . Their Linux Immersive Environment uses a single Linux PC with a video sync-doubler to generate active stereo graphics. The other components -- LCD shutter glasses and tracking -- are equivalent to those in older single-screen projection based displays.
The AGAVE display was developed in parallel with the system described in this paper . Its purpose is to augment Access Grid  displays to allow networked collaborators to share three dimensional content. It uses a front-projected, passive stereo display, and optionally includes tracking.
Z-A Productions market the SASCube as a PC-based CAVE-clone . It is a full four screen, tracked, active stereo system driven by a cluster of PCs. The PCs use workstation class graphics cards (3DLabs Wildcats) in order to support active stereo, video genlocking and swap synchronization of the four walls. The intended markets for the SASCube include museums and public exhibitions.
The Ars Electronica Futurelab are developing the ArsBox PC CAVE. The ArsBox is driven by Linux PCs using sync-doublers for active stereo video. Its purpose is to allow the Futurelab to more easily and affordably deploy art and technology VR applications that they develop for clients.
The HyPI-6 at the Fraunhofer IAO Virtual Reality Laboratory is a dual-platform, 6 sided CAVE-like system . It can be driven by a large SGI Onyx computer, or by a cluster of PCs. The system can also function in both active stereo (when using the Onyx) and passive, polarized stereo (when using the PC cluster).