RPM = CFM?

[oddyager]

is it safe to assume that the higher the RPM the better the CFM, assuming design is relatively the same. Reason I ask is that I think I may need to upgrade the intake and exhaust fans on my case. With a CPU I barely OC'ed (2.2 Ghz on a AMD Venice 3000), my temps are 39-41 on CPU, 51-53 PWM, and 53-55 on my chipset. I've already used Artic SIlver 5 on both cpu and chipset so I figure maybe try to improve on the airflow through my case (don't believe cables are an issue since they are bunched nice and tight away form the board).

My case is a Thermaltake Tsunami and the stock case fans are 120mm listed as 1400 RPM, 21dba, but no info on CFM. Should I look for case fans with higher RPM to improve airflow?

 

[sangyup81]

nah, not all fans are as efficient as the next

and then there are the fan sizes as well

 

[oddyager]

Well I'm in a market for 120mm fans and I couldn't find any info how much air the stock fans for the tsunami pushes and i cant find any manufacturer label on the stock fans themselves (weird?). Im noticing alot of the recommended fans, like Yate Loons have low dba, but also low rpms (explains the low noise level) but that means it wont push as much air, no?

 

[Fullmetal Chocobo]

Yea, in general, that is the rule. The higher the CFM (and RPM), the higher the noise. Some fans are more efficient that others, and can move more air at a bit lower RPM, but CFM is directly proportional to RPM.
Tas.

 

[furballi]

Most of those 120 mm fans are MEDIUM rated...not whisper quiet at full speed. If you can hear the fan running at full speed from 2 meters, then it's probably a medium speed fan.

I'm guessing that you're seeing 40C CPU temp when idling (no Cool n Quiet), and not while running Prime95 using the max heat setting? That's a normal temp. You may not get adequate ventilation to the sensors on the motherboard (SYS and PWM). Or perhaps the sensors are displaying bad numbers.

You may want to invest in a good CPU cooler, like the Zalman 7700Cu, that will blow cold air directly into the motherboard to cool the MOSFETs and the RAMs. You can set the fan at the lowest speed (900 to 1000 rpm) and still achieve very good cooling.

I've just re-adjusted my system to closely match your configuration:

Antec SLK3000B
Abit AX8 board
Zalman 7700Cu cooler at 960 rpm
Cool n Quiet OFF
Winchester 3000 overclocked to 2250 MHz

5% CPU LOAD:
CPU...37C
SYS...37C
PWM...30C

100% CPU LOAD PRIME95 MAX HEAT:
CPU...50C
SYS...38C
PWM...34C

 

[oddyager]

I have an XP-90 + a Panaflo H1a over my CPU that I'm very content with though I'm not 100% thrilled with the CPU temps (was expecting a few more degrees cooler but I think its prolly just the warmer room temp thats causing it). How did you get your cipsets and PWM so cool? Are you referring to a side fan?

 

[furballi]

The Abit AX8 has the MOSFETs, northbridge, CPU, and RAM in one section of the motherboard. The Zalman 7700Cu has a diameter of 5 3/4". This big Zalman 120 mm fan will cool anything within a 4" radius from the center of the CPU.

The Zalman 120 mm draws fresh air from the side duct (Antec SLK3000B). I set the rear Antec 120 mm case fan to LOW. The front 120 mm case fan spins a little faster at 1100 rpm. Also have an Enermax 495 V2.0 with two built-in fan (92 mm and 80 mm). Both are set to the lowest speed (900 rpm).

I think you may have a dead spot in that case, assuming the temperature probe is accurate. Open the side cover and use a small fan to blow fresh air on the motherboard. If there is a significant drop in temp, then you may need to improve air flow within the case.

Immediately check your temps when you first boot in the morning. You should see numbers that are within 2C of the room temperature. A significant deviation usually indicates bad temp probe.

http://www.bestbyteinc.com/prodinfo.asp?number=HSK-ZAL-77C