Then there's memory. This is totally incorrect. Memory speed is only a potential, like a light bulb. If instead you connect it to 240V, there's a good chance it'll fail.
Memory works the same way.
The speed of any synchronous memory system is entirely driven by the memory clock. If you put in 5ns memory, it'll work just dandy, but no faster. If you put in 7ns memory, it might work, it might fail. It might only fail on a hot summer day. But it won't go any slower.