Your drive is PATA, so you can't plug SATA into it. Also, why do you care if a 7200 rpm drive maxes it out? If it doesn't, are you going to go out and buy a 10,000 rpm drive (they do exist, but are almost as expensive as SSDs)?
As an aside, and I just noticed this, why does that optical bay HDD caddy have a DVD logo and button, etc, on the front of it? Are they trying to hide the fact that you now have two HDDs?! 😛