We recently brought up two new web servers. They are both running Windows Server 2003 x64 SP2 with 2 Quad core CPUs and 16 GB of RAM. These machines should really scream... However, ever since we've moved some clients over to them, they've been complaining that they are much slower than the older machines (which were using Windows Server 2003 32-bit). We've had a hard time diagnosing the problem. Here is what we do know?
-The server isn't slow on every page and it isn't even consistently slow on the same page each time. Pages that run fast on other servers are sometimes extremely slow on this machine.
-The HTTP log is producing a large number of Timer_MinBytesPerSecond entries for various pages...many of them being the ones that people are complaining about being slow.
-On other boxes the HTTP log usually only has Timer_ConnectionIdle messages, which from what I understand don't really mean much of anything.
-We copied the IIS configuration from one of the 32-bit boxes that was being replaced.
-The ASP.NET application that runs on these servers is reporting reasonable times (we track how long it takes from when the request comes into the application to when the application finishes the request to find any bottlenecks in the application). So we are reasonably certain the problem does not lie within the application, but rather in the server/network configuration.
-The hardware configuration is almost identical to two other web servers that we have been using for several months now with no problems.
Any help is appreciated, and I will try to respond to any questions as quickly as I can.