We have benchmarked node-uuid on an Intel Core i7 950 @ 3.07GHz processor using the benchmark scripts you can find in the benchmark/ directory, refer to benchmark/README.md to find out how the benchmark was run.
Results are shown in the graph below and you should distinguish between v1 and v4 UUIDs. In general v4 UUIDs are computationally more expensive since they require 122 random bits to be generated for each new UUID whereas for v1 UUIDs you only need 47 + 14 = 61 random bits, which additionally can be pre-generated only once per node.js-process.
While performance of the native libuuid module decreased slightly since the 0.4 branch of node.js performance of the other pure-js implementations perform better with newer versions of node.js. The big exception are node-uuid v4 UUIDs which perform considerably worse starting with node.js v0.5 since node-uuid now uses the newly introduced crypto module instead of V8's native Math.random() which performs poorer but provides much higher quality random numbers.