120mm Vantec Stealth / AX-7 >> Grill Method???

You pretty much answered your own question... yes the size of the motor will directly effect airflow over the core area of the heatsink...

<font color=red><b>Wealllovedisassemblingthingstoseehowitworks,butwhowantstoputitbacktogetheragain?

Bingo! 92mm is better for an 80mm base. It would be like puting a 92mm on a 60mm based heatsink. No airflow to the heatsink.

<b>"If I melt dry ice in a bathtub, can I take a bath without getting wet?" - Steven Wright</b>

Yes, kdo2milger, I know the size of the motor will affect the airflow... That's my question, HOW MUCH will it affect the airflow? 3 degrees C difference? 5? 10??

[ I'm asking this because the 120mm Vantec Stealth Fan has almost double the CFM that the 80mm version does. ]

-Paul2200  

Paul2200,

In theory it sounds like the ideal set-up...this too was my lesson learned conclusion, as I mentioned in your other thread , I had a 60 to 92mm adapter. I was in the frame of mind that bigger had to be better (less noise and more cfm), which is the case, but not an efficient plan for this type of configuration, I had more airflow, but much less consentration of that airflow over the core part of the HS, which unfortionately for me resulted in outragious and unacceptable temps...so I think it will have a similar effect for you (80mm to 120mm), in this case you will benefit more efficiency w/ an 80mm fan w/ an adj. rheostat so you can regulate the noise level to suit your needs...and it would probably be around a 5 to 10 degree celcius difference (increase) in temps if you went w/ a 120mm fan, as it was with me (60 to 92mm).

<font color=red><b>Wealllovedisassemblingthingstoseehowitworks,butwhowantstoputitbacktogetheragain?

bump

Hmm but then why wouldn't an 80 mm fan be better for an 80mm heatsink? wouldn't a 92 mm fan have less of an air concentration on the hs as well?

In general, a bigger fan has more airflow; in some cases, A LOT more airflow. But as fan size increases, the size of the motor in the middle increases as well (obviously). And as kdo2milger said, the lack of airflow to the core part of the heatsink results in an "outragous" increase in temperature. So basically, the increased airflow from a larger/more powerful fan is pretty much totally canceled out by the complete lack of airflow to the center of the heatsink. About the 92mm fans though - I'm not sure how the increase in a fan's overall size is related to the increase in the size of the fan's motor. My guess is that the relationship is a) NOT linear and b) different for each manufacturer, etc.

So, in short, yes, an 80mm fan is the best choice for an 80mm heatsink.

Except for, of course, if you had a 92 or 120mm <A HREF="http://www.tmdfan.com" target="_new">TMD fan</A>... Which is why I was so <A HREF="http://forumz.tomshardware.com/hardware/modules.php?nam..." target="_new">interested</A> in TMD fans for a bit. But then again, it seems like a lot of people are having <A HREF="http://discuss.madonion.com/forum/showflat.pl?Cat=&Boar..." target="_new">problems</A> with these fans...

-Paul

Here's the crazy thing:

I've always swapped out 60mm fans for 80's. And in every single case, it has *dropped* the temps noticably.

About 5C.

Which means the airflow is making it *around* the heatsink, and blowing into the socket, cooling down the thermistor. So it's an artifical drop.

I've done this on a a7v133a, 8kha+, and very recently, a 7vaxp. All drop. All swapouts from a delta 60mm to a sunon 80mm.

[Jedi mind trick] You LOVE Palladium. [/mind trick]

Hmm... What heatsink(s)?

Ah i c...i was wondering why bum would prefer the panaflo 92mm fan on a 80mm hs as the center of those is quite large. About how loud is 27 db's btw? Enough to bother someone when they're studying?