Have a look in the stickied threads, specifically at the 'Breakpoints & Formula's' thread... the first two tables have the FCR breakpoints.
As for "max FPS"... FPS = Frame's Per Second. FPS is constant at 25 Frames (that elapse) Per Second, and it will never vary. Hence, "max" is a useless term in this context. 105% FCR is referring to the 8-frame breakpoint for most sorceress spells (so if it's 8-frames per casting, and 25 frames per second, then at maximum casting speed you can cast spells slightly more than 3 times per second).
The reason that 105% is often mentioned (or often it's 117% FCR for Lightning/ChainLightning sorcs) is because that breakpoint is a reasonably attainable goal for a lot of builds, and it provides some flexible equipment options. The 105% breakpoint can be exceeded, but to reach the point of benefit, you're required to use lots of very specific equipment.
And just to be complete, fyi, the 'breakpoints' are like plateaus. There's no benefit, until you completely reach a higher plateau. So, for example, a sorceress will never cast spells any faster if she has 193% FCR compared to 117% FCR - they'll both yield the same casting speed in every regard. Once she hits 194% FCR, her Lightning and ChainLightning will be a little faster. Once she hits 200+% FCR, every spell will be a little bit faster.