Antec 300 Air Flow

[Poisoner]

Hey guys, I think I might have too much air coming into my case and not enough going out. I recently got some new fans and while I see a difference in how temperatures fall when idle, I don't see a decrease under load. For those who are not familiar with my case, stock it comes with a 120mm fan and a 140mm fan, both exhaust. Which makes about 174 cfm out the case. Well I just put three new fans in my case. I moved the 120mm stock fan and replaced it with a Scythe Slipstream at 110cfm. I took that replaced fan and made it a new intake fan @ 79cfm. I added two more Slipstreams for intake, one at 50% and the other at 100%. I also have my PSU Corsair TX650 acting as exhaust. So after all that, lets add it up.

Intake
110cfm
79cfm
55cfm Total 245cfm

Exhaust
110cfm
95cfm
??? PSU exhaust Total 205 cfm

Do I need to cut some intake fans back? My cable management is good, only thing in the way are the wires that have to be plugged in. I have compared temps before and after and are generally better. But I am concerned about having too much air going into the case and not enough going out.

 

[raygungothic]

If you take into account the reduced intake due to the front filter, and the PSU exhaust, you are probably closer to equal than you might think. If you have a graphics card that vents out of the case back, even more so.

I have a 300 and fairly careful airflow but I'm not overclocking at the moment, so I don't REALLY need to be all that exacting (I'm just trying to make it quiet and stable and last well) - but I notice I do about 5 degrees better with the case sides on than off, which suggests that this case can manage to cool pretty effectively. I fitted a fan control panel and found that my system is overall appreciably quieter when the airflow is balanced, so perhaps tweaking things up and down a bit and comparing the sound might let you know when you're in the right ballpark.

If your idle temperatures have fallen but not your load temperatures, maybe your CPU and/or graphics coolers are the limiting factor rather than case airflow? If you have loads of cool air in your case but your heatsinks can't take heat away from the chips to the cool air fast enough, adding more cool air can't really help that much.

 

[Poisoner]

You are probably right. I guess 36 degrees Celsius under load isn't that bad. I have a cooler master Hyper 212+ and my 4670 doesn't vent out the back of the case but I do have a 4770 on the way that will vent outside the case. I have noticed my video card does overclock without artifacts on the screen now that I added the new fans.

I should just be happy with it. :|

 

[jsc]

All of those flow figures are with the fans at full speed. Are you running them at full speed?

 

[raygungothic]

36 degrees under load sounds not terribly excessive. I reckon, though, that GPU cooling is the only tricky bit in the 300. The front intakes are a long way from the GPU, and the side fan isn't necessarily in the right place and can reduce the effectiveness of the front ones if run too high. I was happier turning mine down, but my graphics card didn't produce as much heat as I had been expecting. If I had a hot graphics card I'd probably be fretting too.

I think it's dangerously easy to get carried away with this sort of thing. I didn't budget for five fans and a fan controller on my build, but I seem to have wound up getting them anyway 😗

 

[Poisoner]

All of those flow figures are with the fans at full speed. Are you running them at full speed?

Yes, they are at full speed. It sounds like a wind tunnel but thats okay. I really need to get some good thermal paste and redo the CPU heatsink. Its just BS I got a best buy cause I messed up when I first installed the heatsink and I had to clean it up and redo it.

 

[debianos]

Poisoner, excuse me if this is too academic, but intake = exhaust. Unless you are building up air pressure inside your case...

The values you list are theoretical or tested values under controlled conditions. If the exhaust fans aren't blowing enough air out, then this creates a backpressure for the intake fans, effectively reducing their flow rate. I think this is what you meant.

Touch your arm. Your body temperature is 37°C. Running your processor at 36°C is like keeping it in your pocket, minus the lint. Overclockers run their temps up to 80°C, which is too hot to touch. Don't worry so much about your airflow until you start pushing your components. And as you say, you would do well to redo the CPU heatsink if you have any doubts on it. You could compare its temperature to other components like the system temp to see the relative effect of load.

 

[dannoddd]

How do you have your cpu cooler situated? Remembering that heat rises, it would be good to have the fan on the heatsink blowing through the fins upwards, into a high cfm exhaust. It would get a push and pull thing going.

Considering the cpu socket might not let you put it that way, have the fan blow from the front of the case to the back, into a high cfm exhaust fan.

It is also possible because your graphics card exhausts into the case, that it is pushing up overall temperatures. You might see a good drop when you get the 4770 in there.

Is your power supply fan facing the floor of the case or upwards? If it is upwards it might be interfering with the overall airflow pattern of the case.

Do you have a fan on the side? If that is an exhaust, try making it an intake.

In my case, a 1200, i have to run my 250mm fan at low because when i turn it on high, i start to get more exhaust than intake, and my temperatures actually go up.

Hope this helps.