CPU cooling pull fan only?

rei · Post by **rei** » Wed Mar 24, 2010 4:57 pm

Using a Scythe Mugen 2vB

Looks like the shop assembling my new PC build says that they can't put a push fan on one side (I wanted to put 2 but the clips don't fit this heatsink) since it is right up against RAM slots with overly-high heatsinks.

Is there any harm wrt to airflow to having only the pull fan out at the other side, near the case exhaust fan?

(Antec Mini P180 case)

So instead of the fan on the right, it'd be on the left, making 2 fans performing exhaust duty.[/img]

rei · Post by **rei** » Wed Mar 24, 2010 5:27 pm

hmm without an intake fan out front to suck in cold air to pass through fins to go through heatpipes to cool the cpu, this would kinda be crappy right?

ces · Post by **ces** » Wed Mar 24, 2010 6:43 pm

Pull the cold air from outside and push it into the heat sink.

Attach the fan to the heat sink and duct the outside air to the fan.

You will get rid of one fan and cool better at the same time.

rei · Post by **rei** » Wed Mar 24, 2010 7:09 pm

Thanks for the feedback. I'll try to clarify:

A is the fan at the rear of the case sucking air out the back.
B is where a fan would normally bad blowing air in from the front.
To the bottom right corner is an intake fan near the bottom-right of the case.

However, B is where a fan won't fit since it is blocked by RAM.
C is where it has to go. It will be taking air to the left as well.

I'm wondering if things will suffer too badly without a fan at B.

I may try to see if the SLIM Scythe case fan will work.

Vicotnik · Post by **Vicotnik** » Wed Mar 24, 2010 7:44 pm

So many fans..

Maybe you have a hot CPU but if it were my system, I would throw out all fans except A.

ces · Post by **ces** » Wed Mar 24, 2010 8:46 pm

rei wrote:Thanks for the feedback. I'll try to clarify:

I understood exactly the problem. It is not that uncommon of a problem.

My proposed solution was uncommon. That is why you may not have fully picked up on it.

It involves reversing the air flow. Feeding cool outside air to the cpu cooler. It may be that you would need to reverse other case fans in the computer to accommodate this change in air flow direction, or you may not, depending on how open the case it.

ces · Post by **ces** » Wed Mar 24, 2010 8:48 pm

rei wrote: I'm wondering if things will suffer too badly without a fan at B.

Depends a lot on unstated factors. I big one being what kind of thermal load are you expecting the cooler to carry.

ces · Post by **ces** » Wed Mar 24, 2010 8:49 pm

rei wrote: I may try to see if the SLIM Scythe case fan will work.

Try that solution first. It's simple and straight forward. Those are the best kind of solutions.

rei · Post by **rei** » Wed Mar 24, 2010 8:58 pm

Ah, thanks for the further feedback. It's just the tower will be a i7 930 chip and the case will have a Radeon HD5850 so running it passively won't be an option. It'll be as quietly active cooling as I can make it with PWM mid-CFM Scythe fans. The tower will also be in a corner so there won't be much room on the air it exhausts as that air may likely collect and heat up the corner--getting as much fresh cool air in is desired.

Or I can see if the techs can substitute "normal" RAM.

Tzupy · Post by **Tzupy** » Thu Mar 25, 2010 12:34 pm

If the case is Mini P180, can't you mount the fan on the lower side of the Mugen2?
You don't have a PSU at the top, and probably don't need the top fan, just the exhaust area.
Well, I just noticed you'll get a 5850 too, so the fan mounted on the Mugen2 would suck a lot of heat from it, so... better not.
Probably the simplest solution would be to get normal sized memory. How about a low voltage 6 GB kit, those won't need heatspreaders?

My Mugen2 cools my i7-920D0 very well, 8 Prime95 threads stabilize at ~50C with Slipstream fans, on it and back case at ~700 rpm.
Unfortunately my Enermax Pro82+ PSU ramps up to 950 rpm when doing this 8 threads Prime95 test.

rei · Post by **rei** » Thu Mar 25, 2010 2:56 pm

Looks like the Scythe Slip-Stream Slim won't work either since the RAM heatsink fins are too tall. I will have to switch to "normal" RAM heatspreaders.

ces · Post by **ces** » Thu Mar 25, 2010 5:47 pm

Prolimatech is coming out with a new cooler that specifically addresses the issue of interfering with RAM.

It's called the Armageddon. You might want to wait for that. Try doing a search on it.

rei · Post by **rei** » Thu Mar 25, 2010 9:41 pm

ugh, replacing heatsink is too much work. going to return the patriot ram for this: http://www.mushkin.com/Memory/Blackline/998679.aspx

rei · Post by **rei** » Fri Mar 26, 2010 8:16 am

Yeah, the RAM is high.[/img]

danimal · Post by **danimal** » Fri Mar 26, 2010 7:13 pm

the cooling sinks on the ram were too high? you can slide the fan upwards slightly.

you could have tried the ces suggestion, i'll try to re-explain it... using the cpu fan in a pull situation, blowing out the back, with a fresh-air duct from the front of the case to the push side of the cpu cooler... you could have had a case fan pushing inwards, at the front of the duct, on the outside of the case.

i mounted a cpu fan on that mugen2 cooler, that was pulling air, and i using the wrong clips you mentioned... it can be done, but you'll bend up the corner of a fin or two doing it.

nomoon · Post by **nomoon** » Fri Mar 26, 2010 8:54 pm

I just installed a fan on an older Ninja using danimal's first suggestion. The RAM was a little tall, so I moved the fan a bit towards the top of the heat sink (away from the motherboard). About 5% of the fan blows over the top of the heat sink. It works fine.

I'm an advocate of the idea that more fans (running slowly) is better than fewer fans running faster. See link here. I wouldn't recommend removing the fan completely, or otherwise your case fans will need to run faster and louder.

Jason

rei · Post by **rei** » Fri Mar 26, 2010 10:55 pm

the ramsink is quite high. trust me, no way to get the clip around the bottom with the ram in the way. i managed to replace the ram with mushkin blackline with slightly more modest heatsinks and was able to move the fan over to the right.

ces · Post by **ces** » Sat Mar 27, 2010 2:10 am

rei wrote:ugh, replacing heatsink is too much work. going to return the patriot ram for this: http://www.mushkin.com/Memory/Blackline/998679.aspx

If you don't mind removing and replacing the same heatsink you can always apply the old "Tin Snip" solution.

The mugen has a huge amount of fin surface. It won't miss a a hundred or two square cm of it. Give it a little trim across the bottom.

peteraugusts · Post by **peteraugusts** » Wed Apr 07, 2010 2:51 am

If you wanted you could do your original idea but turn both fans around and make the back exhaust an intake then build a little duct on the right side of the heatsink leading to the top fan.

colm · Post by **colm** » Wed Apr 07, 2010 9:42 pm

no harm at all.

you could even make a duct of cardboard, cover it with smooth packing tape.. never go expensive.

I am currently at....
26708 hours on my prescott machine. pull fan only, homemade duct.

and to further establish integrity, if any doubts.. the pull method and duct work is the orignal atx standard. it seems to have failed mainstream...because..you may have guessed... too many custom builds and not enough custom ducts to go with them. I am beyond my own belief on this very subject.
the new coolers seem to be the only nice thing to evolve (and you do have a nice one BTW)

build one, it will last..and so will the memory, and northbridge and on and on and on