More on WebFarms and WebGardening in ASP.NET
Had a short conversation over email and John Lam had this to offer around Web Gardens. I checked with Corillian's scalability labs and heard that we have found similar results (we recently more than doubled our previous scalability numbers.)
Web gardens look interesting at first, but I spent a lot of time talking with folks at MS about web gardens and the consensus is that web gardens are only useful on very large SMP boxes – 16-way and up. The reason why is that IIS’s sweet spot is on 4-8 proc boxes. By using web gardens on large (>16 proc) SMP boxes and affinitizing CPU’s, you can make IIS think it’s running on a 4-8 proc box when in fact it’s running on a much larger box.
Fantastic information for anyone who's been disappointed with 16 proc IIS performance or for the two-proc folks who are thinking of adding horsepower.