[tyshy]

Ok....i realized my ys tech fans were way too loud....44db @ 105cfm....keeping my case temp 26C and cpu @ 41C....well i decided to 7 volt the fans...(almost screwing up my hard drive in the process with a 5v going into the ground...i caught that before i turned it back on luckily).....so i did it to both of them....(120mm)...and my other 120mm that came with the case is nice and quiet so i left it alone.

I turn the comp back on and let it run for a few hours or so...i come back and check the temps...and they are 25C 39C....now is it possible that the fans were creating more heat than they were letting out?....i could put my hand in front of the fans and they blew a lot of air....and if i put my finger over the motor it was quite warm...even tho the air coming out wasn't.

so why are my case temps so much lower?....i will tell you tho that it is much less noisy....prolly less than half as loud...im prolly around 34db now.

[tyshy]

bump...any ideas?

[Gautam]

This is intriguing. I use one of those exact same fans on my radiator, but with a rheostat. I also noticed that temps are better when the rheostat is kept somewhere in the middle, rather than at the max. Never figured out why; they only put out 5W or so at their max speed, so this really shouldn't change anything. Who knows, though.

[squirtle632]

OK dumb question of the day.............

If I 7 volt mod my fan and plug it into the same chain as my hard drive.................... what happens??

[ajrettke]

Squirtle:
If your lucky nothing, depending on the circuitry you could fry the board or the motor.

Tyshy:
I think you had probably had a poor layout with the fans and dropping em to 7v got rid of some eddies in the case and caused a more even airflow.

[squirtle632]

Guess I had better change it...........
Been running it like this for about 2 weeks solid.........

OOPS

[L337 M33P]

Wouldn't having the fans go faster mean that the air coming out is more turbulent? That way laminar and directed airflow would suffer and so you probably won't get the air going where it is needed. Pushing less air at 7V will mean that the air isn't going to be as pulverised and so would flow more along the direction of fannage

Just my £0.02

[ajrettke]

Originally posted by squirtle632
Guess I had better change it...........
Been running it like this for about 2 weeks solid.........

OOPS

Hmm I think I might have mis understood your question. The way I read it at first it sounded like the HDD is also 7v modded because of the chain. If that's the case YES CHANGE IT!!! but if you have a "Y" splitter with the HDD on one end and the 7v mod on the other that is fine and shouldn't cause any problems. All the 5v wires all come together at one common point, same for every other wire.

[four4875]

like if you have a through connector for the fans, and switch the - wire to the fan with the +5 wire, as long as you do it on both the plugs, it'll be fune. just dont use a mobo RPM sensor wire when 7 volting a fan, caus the RPM wire normally uses ground pulses, and since you are now using 5 volts instead of ground, you could easliy kill something on the board.

[tyshy]

the whole hard drive issue is because i don't have enough molex connectors on my power supply...so im forced to put the fan on the plug thats usually in the hard drive...i then take the spare plug off the end of the fan...(the extra plug so you don't lose a molex when u connect a fan)....and by switching the plug on the fan to accept 5 volts instead of ground...you have to change the extra plug also so you don't put the 5v into the ground of the hard drive...its pretty simple...just a little extra work...im not brave enough to try it without switching the extra connector...altho im sure the results aren't good.

[tyshy]

Here is a pic of the case and as you can see there is no airflow restriction....all the cables are neatly tied off and the case is virtually clutter free....



the front fan is mounted about 2.5 inches away from the front of the case on brackets i made because the stupid white holder thing was too ugly....and it helped airflow a lot...altho i did this before i modded the fans...this didn't really help temps much.

[Blz]

If your fans were toned down and then cooled more effeciently, couldnt it be assumed that maybe the high cfm of the exhause fans were creating a vaccuum? vaccuums retain heat, am i correct?

This is why joe blow with 20 case fans and the loudest comp in the world can still have the same temps as mr.iknowstuff with his 1 exhaust and 1 intake (properly positioned).


thats my assumption. Negative case pressure = heat, Positive case pressure = cooolness. in most cases that is. doesnt matter if you Raise the intake or lower the exhaust it still seems that a balaced cfm intake and cfm exhaust works best.

[tyshy]

you make a good point....and there is slightly more exhaust cfm than intake....maybe i could put the front back at 12....(loud)....or leave it at 7 and put the other rear fan at 7 and the more powerful rear fan down to 5....i guess it doesn't hurt to try.

[tyshy]

also....i could remount the hard drives in the expansion slot that i took out...its just in front of the upper rear fan...then i could put an 80mm or 92mm in the empty hard drive slot...this way ill have more intake and cool my drives a bit better.


*edit* my 500th post yay!...5 stars now

[Blz]

Tell us how it goes. pc logic makes no sense to real physics brains sometimes, so my gf is going crazy trying to figure out how Less cfm = more cooling. experience speaks for itself so please do share your results.

[ajrettke]

I'm still thinking there were eddies forming (areas where there is no airflow, it just sits there and doesn't move or just spins in circles). I experianced something like this when I add a fan my temps went up.
Also you have negative pressure, which I think is good, but you have almost no new fresh air coming in, that 120 in the front of the case isn't pulling much. Is there anyway you can throw a 80mm or even a 120 on the side pannel of your case? I think putting one that hits your video card, NB and a couple PCI's would be the best

[tyshy]

well i figured out where all the air was going from the front 120mm....it was cooling the video card and all the cards...problem was most of it was getting trapped under the cards and then slowly rising (the case is wide)....so the outtakes would then suck it out...resulting in less air running past the NB and cpu....with a lower cfm it moves the air more slowly and the air has a chance to rise (i can use my hand to sense this)....therefore cooling the nb and cpu a lil better...and the vid card is still cool to the touch...sapphire 9500np @ 324/385


edit** i forgot to mention im going to put in a case window and probably do the do it yourself case window picture...located here... http://forum.oc-forums.com/vb/showth...hreadid=221510

i will be using a different pic obviously....but im gonna put an 80mm ive got lying around on the panel blowing right on the cpu and nb....with a new hsf it should perform nicely...

[Ira32]

That the fans were sucking too much power before, Shortage of power=higher heat. Sucking less power doesnt short other componets of power making it cooooooler

[ajrettke]

Welcome Ira!

Good suggestion but I don't think that is the case. Shortage of power=less stability. Less power also means less voltage/wattage and that means less heat. The current draw of case fans is very negligable compared to that of a HDD or other peripherial.

[tyshy]

Ira....welcome to the forums...but i will have to agree on ajrettke on this...and im not quite sure what u mean?....the less power you put into something...the less energy you are supplying it...so less power to other components would mean less energy and therefore less heat.