Yes & No! - You see having your ram running at 173 as u stated will of course be slower than running at 200, however in my opinion they great to use because it means u can run your HTT at a much higher setting without causing your ram to become unstable, and anyways if u run your HTT at 240 (5:6), your ram will run at 200 (400 effective) and you would have acheived a core of 2.64GHz.