I seen this debate a lot over the years..constant back and forth. What I always see in the debates is if the price is fair and your motherboard supports it then go for it. Timings same?
So to answer your question.. "Noticeable"... Depends on what you run and if you are running tests all day. By yourself/real world I would say no. However if the price is fair and you want any extra gains you can get, your system fully supports it and you use it other than gaming then yes.
What do you use your system for? If this is only for gaming I don't even find 16 gb worth your time. My son plays several games on his computer and they rarely push 4 gs. The most benefit I would say you would see is in compression, video encoding,stress tests, benchmarks etc. Better to spend more money on CPU/GPU/hard-drive in my opinion.
Several tests/benchmarks on this very question that would tell you the same. I recently posted a topic on 1600mhz triple vs 1333 mhz dual and I can't find much reason to care. I believe amd only supports dual channel configurations.
So again I would say no. Now if someone wants to say yes.. I really hope they explain how any jump would be significantly worth it. Going by Newegg.com Kingston memory for 1333mhz vs 2100mhz is about a 11% jump in cost which in my opinion a complete waste of money. For 1600 vs 2400 at 16gbs (cheapest on Newegg and what brand you have) You get about a 21% cost jump. You wont see 11% jump in any gaming and definitely nothing near 21%. However can always shop around I suppose to narrow this gab and make it worthwhile.
I hope my rambling on gave you an answer.