The 3800+ is the newest member of the Manchester strain of the X2 processor family. Technically, its only distinguishing characteristic is the lower CPU speed: 2.0 GHz instead of 2.2 or 2.4 GHz. Thus, this new unit doesn't offer the same level of performance as its senior siblings, but it does convey the benefits of a dual-core design.
This means that except when running more multi-threaded applications, the system remains pretty responsive. In fact, a freeze-up of the operating system owing to heavy loading is hard to imagine.
In many ways, the resulting performance is quite comparable to that of the Pentium D 820. The primary exception is for those applications where Intel CPUs typically shine - audio and video encoding, for example. In those areas, the X2 3800+ can't compete.