http://bulk.fefe.de/scalability/ Conclusion Linux 2.6 scales O(1) in all benchmarks. Words fail me on how impressive this is. If you are using Linux 2.4 right now, switch to Linux 2.6 now! FreeBSD 5.1 has very impressive performance and scalability. I foolishly assumed all BSDs to play in the same league performance-wise, because they all share a lot of code and can incorporate each other's code freely. I was wrong. FreeBSD has by far the best performance of the BSDs and it comes close to Linux 2.6. If you run another BSD on x86, you should switch to FreeBSD! Linux 2.4 is not too bad, but it scales badly for mmap and fork. NetBSD 1.6.1 was treated unfairly by me because I only tested the stable version, not the unstable source tree. I originally only wanted to benchmark stable versions, but deviated with OpenBSD and then with FreeBSD. I should have upgraded NetBSD then, too. Nonetheless, NetBSD feels snappy, performs well overall, although it needs work in the scalability department, judging from the old version I was using. Please note that NetBSD was the only BSD that never crashed or panicked on me, so it gets favourable treatment for that. OpenBSD 3.4 was a real stinker in these tests. The installation routine sucks, the disk performance sucks, the kernel was unstable, and in the network scalability department it was even outperformed by it's father, NetBSD. OpenBSD also gets points deducted for the sabotage they did to their IPv6 stack. If you are using OpenBSD, you should move away now. -- Diego Saravia [email protected]