Linkbot 4.0 boasts an improved engine, one optimized to check links more quickly than previous versions did. In our testing, though, this didn't bear out. Running Linkbot 3.6 and 4.0 in similar conditions gave nearly identical results. Still, both versions are plenty fast. Using 10 connections on a T1 line, both averaged around 250 links per minute.
Results vary by time of day and server traffic.
When we ran Linkbot 4.0 on the local copy of our site, we averaged more than 1,000 links per minute. While Linkbot has been tuned to use less memory, having a large amount of RAM is still important when checking huge sites. Tetranet recommends 64MB to check 50,000 pages and 256MB for 1,000,000 pages. Prior versions of Linkbot have choked over URLs created in JavaScript, but that is also remedied here. It takes a little fine tuning, but Linkbot can be set to understand what a site's JavaScript URLs look like within a script.