Noctua NH-D14

Hi, I got my Noctua NH-D14 recently and decided to OC my i7 920 to 4.0 Ghz. I need an opinion on my results (preferably from people who understand the i7s heat compared to other chips and people who used i7s).

[LOAD] 4.0 Ghz Noctua NH-D14 Both Fans (30 minutes of small ffts on prime 95):

Maxed out at 75C, that was pretty much the average too.

[IDLE] 2.4 Ghz Noctua NH-D14 Both Fans (30 minutes of idling):

Average was 35C

Are those results normal for an i7 using the bloomfield chip? I've looked it up on a few websites but their results seem to be quite lower, maybe I didn't mount it tight enough or apply my paste properly? (I was replacing the cooler, and I used rubbing alcohol with some Q tips to remove the previos AS5 and reapply it).

Thanks.

ps. Is there any reason I would not want it to scale me back to 2.4 Ghz during Idle? Does the setting that's doing this scale my speed depending on what I'm doing often or would it better performance wise to keep it at 4.0?