Airflow question

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keldegar

Limp Gawd
Joined
Dec 11, 2006
Messages
339
Here's my setup:

Q9550 @ 3.4Ghz (1.25V in BIOS)
Gigabyte GA-EP45-UD3P
8GB G.Skill DDR2-1066 @ 960Mhz 5-5-5-15
Sapphire Radeon HD4870 1G [stock speeds]
Western Digital Caviar Blue 640GB Hard drive
Antec Solo Plus 550 case.

I have the Antec TriCool 120mm fan on low exhausting and a Xigmatek Dark Knight S1283 with the fan pointing towards the exhaust. The system is extremely quiet.

My idle temps are 38-40C and load 58-61C. If I remove the side of the case, the load temps drop to 53-55C. Ambient is around 80F. Hard drive temp is 41C.

The case has spots for 2 92mm intake fans. How do you guys think I can improve the temps without adding too much noise?

Thanks.
 
Not having the front fans in use is hurting you, most definitely. Cool air in the front, hot air out the back/top, that's the plan. Put the 92mm fans in, get it all set up, close the case and watch the temps drop pretty dramatically. If the noise is too much, look into getting a rheostat controller to adjust the fans, but don't let 'em sit there unused, your system can't breathe at this point without 'em.

The fan in the back isn't designed to suck cold air in and throughout the case, it's just meant to exhaust what's already inside, get those 92mm fans pushing in the cold stuff and your temps will probably go down 5-10C quick.
 
Thanks for the response. Do you have any suggestions on high CFM low noise fans?
 
If you really want quiet fans, modify the 92mm holes to fit 120mm fan(s). Even if you can fit only 1, larger fans are more efficient (dB/CFM ratio) than smaller fans.

If that's not an option, because you don't want to cut the metal, noctua fans are worth a look. Expensive, but effective. In 92 or 120mm sizes...
 
The 120mm on low is a problem if you are not going to use front intake fans. A single exhaust fan is OK if and only if it puts out enough air to still suck in air from the front. The TriCool fan on low definitely does not do this.

You are also probably having an issue with the S1283 fan displacing more air than the rear fan can exhaust. More intake would not solve this problem, although it would theoretically lower your temperatures.
 
Arcanide said:
You are also probably having an issue with the S1283 fan displacing more air than the rear fan can exhaust. More intake would not solve this problem, although it would theoretically lower your temperatures.
Click to expand...

That is a very good point, I hadn't thought of that. I think on medium it's too loud for me though, I will try it and see how much if affects temps. It makes sense that the S1283 is overpowering the exhaust because the hot air is staying in the case (when I take the side off it drops so much). However I am fine with the current temps if it means my system will be silent as it is right now.

I bought 2 evercool 92mm fans at a local shop (2200rpm) and they are way too loud. I didn't wanna have to wait for an online order, and they were only $8 each. I plugged both into 3pin motherboard connectors and it was soooo loud. (2250rpm in BIOS). It definitely made a difference though (idle dropped to 36C, load 56C) I tried plugging 1 into the 4pin connector on my motherboard and it was much better (1500rpm). With the 1 intake fan at low rpm I'm getting around 38C idle-58C max.

However, my motherboard only has 1 4pin connector, how can I run my 2nd intake fan at lower rpm? at 1500 i can barely hear it, so that works for me. Is there something I can do to undervolt it? (it came with the molex adapter). or should I just invest in a fan controller because i'm so obsessive about the sound?
 
Nice temps, i think those are right where you want to be, i'd try a NB/SB cooling solution those puppies give off a ton of heat, sounds like you got everything else covered.
 
If you want that other fan at a slower speed and don't care about RPM sensing, you could run it off the 5V rail. I'm doing this on all my 120mm case fans and they are silent.
 
4x4not said:
If you want that other fan at a slower speed and don't care about RPM sensing, you could run it off the 5V rail. I'm doing this on all my 120mm case fans and they are silent.
Click to expand...

could you explain more?
 
keldegar said:
could you explain more?
Click to expand...
When you run a fan off a lower voltage, it reduces the speed it runs at so it makes less noise. It also pushes less air, but it's better to have some airflow at a reduced noise level than to have none at all.
 
Zero82z said:
When you run a fan off a lower voltage, it reduces the speed it runs at so it makes less noise. It also pushes less air, but it's better to have some airflow at a reduced noise level than to have none at all.
Click to expand...

I meant how do you run it off 5V? the 3pin connector is 12V.
 
keldegar said:
I meant how do you run it off 5V? the 3pin connector is 12V.
Click to expand...
You use a 3-pin to molex adapter, then you take the part of the adapter that connects to the PSU and you swap the positions of the pins connected to the red and yellow wires. It's fairly easy to do; all you need is a small screwdriver and some patience.
 
Zero82z said:
You use a 3-pin to molex adapter, then you take the part of the adapter that connects to the PSU and you swap the positions of the pins connected to the red and yellow wires. It's fairly easy to do; all you need is a small screwdriver and some patience.
Click to expand...

I read that the rest of the voltage goes back to the PSU if you do that, which can damage it. Should I just invest in a fan controller?
 
keldegar said:
I read that the rest of the voltage goes back to the PSU if you do that, which can damage it. Should I just invest in a fan controller?
Click to expand...
That would only be true if you grounded to one of the positive voltage wires from another positive voltage wire (which is actually how people run at 7V; they ground the +12V to the +5V which gives +7V). Which isn't great for the PSU, but it won't really harm anything. However, when you run a fan at 5V, you're grounding the +5V wire to a normal neutral ground wire, so you won't have to worry about harming the PSU.
 
Zero82z said:
That would only be true if you grounded to one of the positive voltage wires from another positive voltage wire (which is actually how people run at 7V; they ground the +12V to the +5V which gives +7V). Which isn't great for the PSU, but it won't really harm anything. However, when you run a fan at 5V, you're grounding the +5V wire to a normal neutral ground wire, so you won't have to worry about harming the PSU.
Click to expand...

thank you for this information :)

my CPU is currently @ 38C idle, hard drive is down to 35C now... that intake fan is really helping. I'll see if i can get the 2nd one going at 5V.
 
Just make sure that if you do the wire swap, you don't use the passthrough side of the adapter to plug in any devices, because it'll fry them.
 
I did a small experiment once and found that having an additional case fan blowing towards my 1283(with it's own fan) lowered my temps by about 5 degree's. The problem is my case isn't designed to have a case fan that far up.

You could look at a solution where you can attach a couple case fans into your 5 1/4 inch bays and blow air towards your heat sink. You want your heat sink blowing cold air, not just recycled internal case air, which it's doing now.
 
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