Well, as far as the Noctua is concerned... I think you can do better than the Noctua, they've fallen a bit behind some of their competitors in that regard. Consider the Zalman CNPS14X with the addition of an extra 140mm fans (I'd personally recommend a Xigmatek XAF-1451 for its light weight, good static pressure, and high airflow to noise levels (90.3CFM at 18dBA))... it would come in significantly cheaper than the Noctua's circa $90 price tag with equal or better performance.http://pcpartpicker.com/p/1dP7e
As far as the 8520 it probably won't compete with the 3770K as well as the 8550. We'll get an idea of what Steamroller performance will be like with the launch of the Kaveri APUs around the holidays, but the Steamroller desktops have likely been set back until at least Q1 of next year. It really depends on several things.
First. Your budget. If your budget allows it, I would recommend also considering an X79 build with an i7-3820 since LGA 2011 still has some longevity in it with IB-E and Haswell-E both currently planned to be on that socket giving you a more flexible upgrade path, whereas the 3770K (1155) and the Steamroller (AM3+) officially being the last generations on their respective sockets.
Second. Steamroller desktops probably aren't going to be out until at least Feb/March, so it might prove more beneficial to wait an extra 3 months at least before you upgrade.
Third. Going back to the considerations of the LGA 2011, the i7-3820 performs within 5-10% of what the 3770K does, for about $90-100 less (currently available in-store at Microcenter for $230)... So the better upgrade path and the proven on par performance with what is projected
for Steamroller make it a more viable option than Steamroller imho, since it has the better upgrade path, nearly identical cost/performance value, and the added perk that the SB-E prices will probably drop even more once IB-E is released in several months.
Just my thoughts.Edited by SpacemanSpliff - 7/6/13 at 9:06am