Ashish, While I applaud your efforts I've got some points that may call into question the performance differences:
1) I only see debug directories, not release. Performance testing a debug build is silly, there are optimizations that the compiler and JIT ignore in debug that can make a huge performance difference. 2) If I'm reading it right, you use a single stringbuilder in the spring test, but you build a new one for each iteration in the log4net test. That right there will kill you. And actually .NET's String.Concat is optimized for up to 4 strings so you're better off coding CriticalErrorLog.WriteLine() as: return string.Concat(message, " ", method); 3) nSpring seems to do async logging. That is, the log method returns before the log message is written to disk. If you want to check that, bring up task manager, run your test and log 1,000,000 messages. Then when the test app claims it's finished kill the process in taskman. When I did this I didn't even get the log file, let alone one w/1M rows in it. -Walden -- Walden H Leverich III Tech Software (516) 627-3800 x3051 wald...@techsoftinc.com http://www.TechSoftInc.com Quiquid latine dictum sit altum viditur. (Whatever is said in Latin seems profound.)