Area optimization in Quartus II

Ahhh. I thought a warning message popped up when you opened a project with a .qsf in read-only mode. But that certainly makes sense.

It's obviously a trade-off, i.e. if you really need to optimize for speed to meet timing then you can't do area also. But you can make assignments on a hierarchical basis. So, for example, if your main setting is speed, go to a hierarchy you know meets timing and right-click -> Locate -> Assignment Editor. THe AE will come up with the hierarchy name at the top. Copy it into the To column, select the assignment Optimization Technique and set it to Area. Repeat as necessary.

Also note that Balanced is a really good option. It's not a mid-way point, but often gets near the best of both. Basically it does the speed optimizations that don't have a significant impact on area, and does the area optimizations that don't have a significant impact on speed. Definitely worth a try.