Speed? Scalability? (Score 1)

Do any of the OpenSource CMS's scale well? For the longest time, I was going to release the one I wrote simply so I could give it the name OpenSTFU. What I discovered is that a lot of programming compromises have to be made to create a CMS that's flexible enough to fit the needs of many people. I eventually gave up trying to make something for mass-consumption, and kept my CMS private. There would easily be three times the amount of code involved to make it a reasonable choice for other people to use. In my experience, flexibility was synonymous with slow, since extra CPU cycles were needed on every page. The CMS suffered from trying to be a Swiss Army knife.

I'm sure some of that can be fixed with better programming and design, but is that happening with the free, modern CMS?