They're NZXT FN V2s all running at 100% because it doesn't really seem worth undervolting the stock fans imo when I can get better quality stuff. So 1200RPM (+/- 15%) all the time. The 140 will be 1000RPM (+/- 15%) all the time.
Well, broadly speaking you can't compare 1000/1200rpm fans (NZXT) with 7V fans (BQ), to say those latter are unsatisfactory, you should compare both within the same metric, rpm or volt.
Again, broadly speaking, whether it's true that at 1000/1200rpm some fans (like - you say - those NZXT, but I can name several Cooler Master or Enermax ones) may have a nasty "sound signature", *any* large fan at 1000/1200rpm is quite noticeable, even better, in my humble opinion it is loud.
So if you want a very quiet setup, you will pay an hefty temps penalty; on the contrary, with much more comfortable temps, you will get a moderately noisy system (per SPCR standards).
In my experience I strieve to not pass 600-700rpm with 120mm fans, and to not pass 500-600rpm with 140mm fans: in my opinion, above these limits, a system cannot be called "quiet".
But at these mentioned speeds, you will have a pretty toasty rig, and if I understood you correctly, you don't want that, do you?
Next step could be trying upper limits, maybe around 800rpm for 120mm fans, 700rpm for 140mm fans: if I were you, using either the MSI UEFI/software, or SpeedFan (which usually works on MSI boards), I would make some tests manually fixing the fan speeds at those limits, in order to record which will be the actual heating.
As suggested by several other co-forumers, if you have top exhaust fans, I would perform those test both with those ones as exhaust, and with those ones flipped as intakes (even if, by your after-stressing temps with the sides in, it would seem that you mainly lack some exhaust prowess).
All these tests should help you to determine a temperatures baseline, which is necessary to evaluate any possible better candidate (or cooling strategy). Obviously, IMHO.
Thanks for taking the time to reply.
I'll happily concede I'm comparing apples to oranges when attempting to compare stock 1000/1200rpm fans with 7v Bequiets (700ish rpm), but the other comparison to the Aerocool fans remains. I tested these at both 7v and 5v and the gpu/cpu never got any higher under load than the stock fans do at max rpm, which lends credence to the suggestion I can fully equip my fan slots, running the new fans [whatever they may be] at a lower rpm, and maintain temps (or at least, not sacrifice too many degrees). Having fans controlled would mean I can always turn them up when gaming and such when peace and quiet doesn't matter, should the temps be overly high.
With regard to 'I don't want a toasty rig' this is partially true. I'll quite happily sacrifice non-load temps so that I can work at my desk on office applications and read textbooks in peace, gaming isn't so much of an issue as I'll have speakers or headphones on.
I think, as you said,
the next step is to set some baseline temps to work off by attaching my current 4 stock fans to the 4 headers I have spare, setting their speeds in the BIOS and doing some tests to see what I should be aiming for.EDIT**
Plugged all my fans into the headers and switched them all down to 800rpm (lowest i can get them for some reason, even though 50% of 1200 is definitely not 800rpm). CPU load is 65C, idle 32-34C. GPU 32-34C idle, 77 C load. It is a bit cooler ambient than it has been, so I can probably add a few degrees onto those for a hot day. After stressing the GPU, idle temps for the CPU seemed to stay around 38-40 and took a good 10 minutes to drop down again whilst the fans tried to get rid of all the hot air.
This seems like a good base level to aim for and although the sound profile is poor, the actual noise level isn't bad, and its performing much better than the silent wings, and about the same as the aerocools.EDIT 2**
Updated original post for clarity.