cfm differences

How much differences would the cfm of a fan make? Would 10 more cfm of air flow make a significant difference? I know that the decibal scale is exponential and I was wondering if the cfm is similar.

Cooling by CFM rating is linear. A 30 CFM fan will cool about 150% better than a 20 CFM fan. This doesn't apply to RPM ratings, though. RPM ratings are pretty much useless aside from monitoring the fan. But I'm sure you already knew that.

Oh wow, I didn't realize it would make that much difference. So getting a fan with a 10 higher cfm would make a BIG difference....

Well, no. It depends on the ratio, not the difference. 30 CFM will push 50% more air than 20 CFM, but 90 CFM will only push 12.5% more air than 80 CFM. Also, if you're using the fan on a heatsink, beware the dead spot. The larger the fan (60mm, 80mm, 92mm), the larger the dead spot, which will decrease cooling immediately around the CPU core.

and then there is static pressure... or something like that

I have two of these case fans http://directron.com/4412fgl.html and I am thinking about getting these http://www.performance-pcs.com/cata...d=477&osCsid=1d87f7759dd4291f8078a31255a60286. or another panaflo. I'm not sure what the difference between these two are since the directron site seems to measure the cfm weird.

The ones I'm really looking for is a 92mm heatsink fan, I have this http://svc.com/92bluredquad.html and am thinking about getting this http://www.performance-pcs.com/cata...d=465&osCsid=aa6dcdc29ba287aac667367c0172f6e0. This difference in cfms is about 10, so do you think there would be a noticable difference?

The difference between the two types of 120mm fans is that the second one pushes TWICE the air of the first. Directron measures the airflow in both m3/h and CFM - the CFM rating is 55.3. Two Panaflos will push roughly twice the air, but in this case the cooling effectiveness is more dependent on where they're located in your case, and whether they pull air in or push it out. Things like air pressure, where your case is, and how many other fans/holes you have. To get the most airflow, both should be pointing in the same direction (into or out of the case), but that might put a strain on the fans, or suck in too much dust, if you don't have enough fans in the opposite direction.

As for that CPU fan, the latter one will obviously cool the heatsink better. What heatsink do you have? I think anything short of an SLK-800 might be affected too much by the dead spot. You should go for a Thermaltake Smart Fan II, which is an 80mm fan. It pushes 75 CFM at full speed (but it's loud) and can be adjusted manually or automatically to anywhere between there and 20.5 CFM. Plus, the dead spott will be smaller.

You can also eliminate the dead spot by using a duct.

I have an slk-900A for my heatsink. Will the deadspot be really bad on it? So would getting another 92mm fan be worth it such as the one in the link before?

Would the case fans be worth it? One will be intake the other exhaust. Intake fan is at the bottom front, exhaust is at the top back.

Oh and how do you make a duct? How effective is it?

So would getting higher cfm fans be worth it for me or would they just be noisier without providing much of a temp difference?

depends on how much more cfm...

If you check the links in my post above, all that info is provided. Here are the links again.

Mystypiy said:

I have two of these case fans http://directron.com/4412fgl.html and I am thinking about getting these http://www.performance-pcs.com/cata...d=477&osCsid=1d87f7759dd4291f8078a31255a60286. or another panaflo. I'm not sure what the difference between these two are since the directron site seems to measure the cfm weird.

The ones I'm really looking for is a 92mm heatsink fan, I have this http://svc.com/92bluredquad.html and am thinking about getting this http://www.performance-pcs.com/cata...d=465&osCsid=aa6dcdc29ba287aac667367c0172f6e0. This difference in cfms is about 10, so do you think there would be a noticable difference?

Click to expand...

i knew that

I can vouch that that panaflow is very quiet. I don't have a LED fan to compare it to and since they both are about the same DBA and the panaflow pushes more air, i would get the panaflow. it works great with my SLK

There is definetly a reasonable difference in cooling abilities of fans with greater CFM. But then do you want that extra noise?

Thank You,
Daniel

Panflow Noise 35 dB(A) Air Flow 56.8 CFM
92x25mm Blue / Red Quad LED Fan Noise Level: 34.50 dBA Air Flow: 48.11 CFM

0.5 dba 9 more cfm.... worth it IMO