If you're concerned I would rma it since it's still under warranty.

1. Maybe, maybe not..It's not good, but any fan could last a long time and just be noisy.
 
2. From page 3 of the User Manual: The 650BQ/750BQ/850BQ comes equipped with the most comprehensive protection set possible, including Over Voltage Protection (OVP), Under Voltage Protection (UVP), Over Power Protection (OPP), Short Circuit Protection (SCP), Over Temperature Protection (OTP), and Over Current Protection (OCP). This product is also covered by a 5-year warranty and EVGA’s legendary customer service and support..Let's just say that it 'should' shut down if it ever gets too hot.
 
3. For sure.

Thanks for the feedback.  I'll probably put in a support ticket.
 
Follow-up question, though.  As I noted in my original post, I only got the 750 BQ because it was the best choice from the empty shelves when building this PC last year.  Let's say I use this an an excuse to upgrade.  I would have preferred an 80Plus Gold.  Looking at the EVGA product page for 750 Gold, there are a lot of options (and the pricing isn't bad.. I think they may even be the same or cheaper than I paid for the BQ)...
1. Looking at EVGA's 750 Gold options, there are a lot of choices.  I'm struggling to find meaningful differences between the different models.  There's the G+, G6, G5, GA, and G3, to name a few.  A few have fluid dynamic bearings instead of ball bearings, so that suggests G+, G5, & G6 are "better".  The G+ and G5 have sleeved cables instead of flat, so are they better than G6?  And then the G5 has eco mode whereas G+ does not.  So, G5 is the "best" of the bunch?  Are those really the only differences between these PSUs?  Fan bearing, cable sleeving, and eco mode?  Should I get the G5?  Is there some other meaningful difference I'm missing here? (It's an odd thought that "G5" might be better than "G6"... your normal thought process is "higher is better", but doesn't appear that way in this case...)
2. Is it worth doing the upgrade?  The Gold rating should save some electricity over time and eventually pay back.  However, how useful will the PSU be in 4-5 years?  I'm asking this question in reference to ATX12VO.  Has anyone heard whether it's actually coming?  I'd hate to purchase a better PSU "to futureproof" and then it's not useful in a couple years if they switch to the new standard.  (Then again, if the rumors that the 4000 series NVidia cards will be like twice the power draw are true, 750W won't be enough... so maybe it's a fools errand anyhow.)
 
Thanks.

bob16314
Or change the fan in your BQ if you know how and accept the risks/hazards of working inside a PSU, and warranty would be voided if you did that.

I had that thought, but I know there are risks and I'm not familiar with what they are exactly / how to mitigate them.  I'm guessing it's the capacitors and that there's some means of discharging them safely, but I barely trust myself with electrical work when I have the breaker switched much less this. :)
 
 

I'm going to dig back up my old post just to provide a status update.  I ended up RMAing the PSU, getting a shiny new one with no fan rattle.  However, after a few months, the new one also incurred the same fan rattle.  It makes me think that perhaps the fans on the BQ series are just trash?  Was I just unlucky?
I guess, based on my sample size of two, I would advise against the BQ line of PSUs.

I have a 700 80+ Bronze unit that is just over a year in use.  I just noticed that the fan makes a small amount of noise until it has run for 10min or so.  After that it the noise goes away.  I am confident that it is fan noise.  This unit has run for most of the year at about 200W to 250W.  The last few weeks to couple of months, it has run at 400W to 500W.  The unit case gets warmer at the higher load; yet, it is not overly hot to the touch (i.e. I am not burned when I touch it...).  I am wondering about an RMW as I have another of the same units that has been used at similar loads and usage time and it does not have the fan noise.
 
What do you folks think?