FAN MOD on MoBo tray side of case???

RADARADA Apple Valley, CA Member
edited December 2003 in Hardware
What's up, y'all,

Has anybody here ever modded their case to include a fan on the tray/MoBo side? If your looking at the front of a standard ATX case, it would be the rigth side.

I'm wondering if cutting a 80mm hole in both the case and MoBo tray, and isntalling a good 80mm fan, to curculate air across the bottom of the MoBo, would have a positive, negative, or neutral effect on system temps.

Any of you guys done this, or have info on it being done?

Thanks!

Later,

-R-

Comments

  • ketoketo Occupied. Or is it preoccupied? Icrontian
    edited December 2003
    I'll have to go trolling to find it, it's on the [H]ardOCP forums, but there's a long post on just this subject. The original post'er suggests a dramatic improvement, most people get *some* improvement if cooling directly on the bottom of the socket and have access to outside air, ie a hole in that side of the case as well as the mobo.

    Haven't done it myself.
  • RADARADA Apple Valley, CA Member
    edited December 2003
    I've seen a post on overclockers.com, where a guy made a custom water block to cool his Northbridge from the back side of the MoBo, very informative, and worked very well, but I don't the tools, skills, or desire to go that far! :) It did give me the idea of adding some airflow to the back of the MoBo though. Just wanted some feedback on whether this works or not, before I go chopping up my case!
  • NoFutureNoFuture In a 3D world...
    edited December 2003
    I'd say just try it !

    If correctly done, IMO, it can only do good...
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited December 2003
    RADA- want my guess? I'd say it'll cool the back of the board, but not much else.

    In doing some testing with that blower setup I have, guess what I found? The really, REALLY high power fans (the Vantec Tornado 92mm, especially) I used caused an interesting phenomenon. Instead of the MBM5 CPU temperature being off the actual temperature by say, 1-5*F (actual temp. read using a DigiDoc5 and a thermal probe taped to the CPU core), it was off by 10*F or more in some cases.

    I don't have a solid explanation for this, but I have a theory: The high-flow fans cool down not only the heatsink and the CPU, but also the socket more than smaller fans do; the NF7-S appears to be reading temperatures from the in-socket thermistor still (don't ask me why...), and if so, that would explain the temperature difference.

    Where am I going with this?

    Well, if cooling the socket throws your temperature readings off, and cooling the back of the board cools the socket (which it will), I'm betting that most of the "huge impact" people attribute to this mod is nothing more than a statistical anomoly.
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited December 2003
    And there you have the explanation to the success of the heatsinks who have a bigger fan than the actual heatsink.

    You guys who praise the Thermalright will cut my knees now but i'm saying it's a damn hype and this is the explanation.
  • Geeky1Geeky1 University of the Pacific (Stockton, CA, USA)
    edited December 2003
    Mackanz, it is not all hype. I've done the testing to prove it, too. I'm just not quite ready to post the final results yet.
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited December 2003
    So are you saying a 80mm fan at 50cfm perform the same as a 60mm at the same cfm? (which it should)

    Edit//** I hate threadcrapping and i just did it to the fullest extent. Please excuse me RADA.
  • MediaManMediaMan Powered by loose parts.
    edited December 2003
    Wow...a 60mm. fan pushing 50 cfm? That'd be loud. :eek2:

    It would be a question of size of the heatsink. Ratio of heatsink length and width vs. fan area.

    Given two identical heatsinks 60mm. x 60mm. then the heatsink with the 60mm. fan would perform better due to the fact that there would be less "spillage" of air onto the heatsink fins. Remember that the core spindle of the 80mm. is larger.

    Given two identical heatsinks 70 or 80mm. square then the 80mm. fan would perform better.


    But that's not the question. The question, if I'm right, is would a fan on the backside CPU area blowing air onto the motherboard aid in cooling? Simple answer...yes. But would the effort be worth it? No...unless you are a modder like most of us with too much time on our hands. :)

    It may disrupt optimum PC case airflow a bit though.
  • TheLostSwedeTheLostSwede Trondheim, Norway Icrontian
    edited December 2003
    Mediaman,

    Are you on some sort of PDA and typing?
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