is a top Blowhole useful or needed?

[TitusTroy]

I have a Lian Li A70-B case and I purchased the optional top panel which comes with 2 blowhole's...I'm planning on adding 2 exhaust fans on top...will this help airflow or hinder it?...I know that heat rises but I heard that for a case with a lot of fans inside that a top blowhole may hurt as it could create unecessary currents...my current case has 2 intake fans in front, 2 in the middle over the graphics card/hard drive area, 1 outtake in the back...would getting the blowhole be of any help to me as far as cooling/performance

or should I just keep the regular top panel which does ot come with any blowholes on top?...any help appreciated

 

[Zepper]

Must be using OPM. One doesn't buy stuff without considering the ramifications with one's own, hard-earned, money... Generally, and not very intuitively, blow holes aren't very effective and provide an opportunity for Murphy's Law to kick in. Call us once you've fed your system a beer or a coke or some Lucky Charms with milk down the new holes.. ;-)

.bh.

 

[TitusTroy]

I'm not going to spill anything down the blowhole so that's the last thing I'm worried about...I'm more concerned with whether or not it helps in terms of cooling...it's a scientific fact that heat rises so one would think a blowhole could have a major positive effect on cooling...even without an exhaust fan on top just having the blowhole could help heat escape naturally

 

[yh125d]

With 4 intake fans and only two exhaust I'd definitely put the extra exhaust fans on. Get something low RPM or variable though, as they will likely be the loudest fans in your case since they're at the top looking at you (assuming your case in on the floor/low

 

[Eureka]

With the RC-690, I found that the extra blowholes aren't doing that much. I have the top two fans connected to a fan controller, I only see maybe a 1C drop in CPU temp when both are on. On the other hand, I have an intake fan in the drive bays pointing towards the CPU. When that goes on, I see a 3C drop in CPU temp.

 

[daw123]

The perfect place to mount a 240mm rad (for liquid cooling) with two 120mm fans

http://i429.photobucket.com/al...wilson123/IMG_0931.jpg
btw mine's a PC-A70A with a 360mm rad and fans in the top

 

[BonzaiDuck]

Not attempting to "dis" anyone here, and I didn't see any posts that departed from common-sense.

Here's my view of this. A few good case manufacturers, like CM and Lian-Li, may give you superb designs with a lot of cooling-vent options. But it may be the case that you don't need all of them. It's a matter of CFM[in] > CFM[out] -- (pressurizing the case slightly) and directing the airflow through narrower apertures focused on the heat sources. Here, I'd give my big dissertation on motherboard ducting, but with some of these cases (like the Stacker 830 line, the HAF, etc.) you may get the same effect without building ducts.

On my CM 830, I simply blocked off the top blowhole with a piece of black foam art-board (which I use to build either finished ducts or prototypes anticipating the use of Lexan panels). In that particular case, the greater intake CFM's (slightly pressurizing the case) forces air through the PSU in addition to cooling the components. And I never finished the ducting plan I had for that case.

I have an E8600 Wolfdale OC'd to 4.25 Ghz, and the load temperatures with LinPack or IntelBurnTest don't exceed 68C even when the room-ambient closes in on 80+F.

 

[Cannyone]

I normally like to keep just a little bit of "positive" air pressure inside the case. As it helps keep the dust out. At the same time I've done my own blow holes many times in the past and they almost always improved my "in case" temps by a couple degrees. What I would recommend is that you calculate the total CFM in and out of the case. And get fans that keep them close, with a little extra "In". At the same time you need to consider how to increase the intake of "fresh air". As that will most effectively help your cooling. But generally speaking... just pulling hot air out is not that effective.

Side Note: After many years of modding cases, Cooler Master finally made a case which is just what I wanted > the HAF 932. And yes while it has no filters, I don't consider that to be a problem. I clean my cases out at least once a month anyway. Still my temps are really good, I love this case!

 

[videogames101]

I'd like to point out that positive pressure may keep dust out, but can also create hot air pockets, etc. I'm fairly sure negative pressure results in better cooling, but more dust.

 

[yh125d]

Theres no proof that pos or neg is necessarily better. As long as its going the right places

 

[Modelworks]

Heat rises, but that is only when there is nothing to push it around. Put a fan in the case at the top blowing down and the heat will go down not up

The whole positive/negative air flow thing is moot. All that matters is how much cool air you are bringing onto the heatsink and how fast you are removing it.