XP-120 CFMage?

[Vegitto]

How much CFM will an XP-120 benefit from? I mean, is there some kind of overkill on an XP-120? After how much CFM will you no longer see a benefit? 100 CFM? 120? 150? 200?

 

[JBDan]

Good ques. I would think around 80-100 and after that, limited benefits with your new jet airplane. Just an educated guess.

 

[Vegitto]

Originally posted by: JBDan
Good ques. I would think around 80-100 and after that, limited benefits with your new jet airplane. Just an educated guess.

Really? So that 220 CFM monster I had planned wouldn't benefit me over a ~120 CFM fan?

 

[JBDan]

lol what are you trying to cool? Maybe someone else that has used a higher than 80-100 cfm fan can help you. I have the xp120 and have never needed more than 40cfm to cool my oc'd 3500+, BUT your case temps are the major factor. If your case temps are warm, you could throw 300cfm IMO at your cpu and it still won't make a difference. Its all about your case temp (translates to room temp+case airflow).

 

[ericlala]

woah way too technical for me. i set it to as quiet as possible without overheating anything

 

[Vegitto]

Originally posted by: JBDan
lol what are you trying to cool? Maybe someone else that has used a higher than 80-100 cfm fan can help you. I have the xp120 and have never needed more than 40cfm to cool my oc'd 3500+, BUT your case temps are the major factor. If your case temps are warm, you could throw 300cfm IMO at your cpu and it still won't make a difference. Its all about your case temp (translates to room temp+case airflow).

Well, the room temp in here is really high.

 

[JBDan]

Then you might see a 1-3C under load difference by jumping up to the 220cfm bohemoth from Delta.

 

[coomar]

i remember from an earlier thread that people mentioned that too high cfms tended to increase temperatures, something about totally disrupting airflow inside the card, it would be like having a hurricane inside there

 

[Vegitto]

How much CFM should be the max for an XP-120, then?

 

[Vegitto]

OMFGWTFBBQBUMP!

 

[Bona Fide]

Just get a 120cfm Delta...honestly, you won't see much difference between 100 and 200cfm. Maybe a couple degrees, and around 25-30dBa.

 

[Bull Dog]

I have a Panaflo 120mm (the L, Low speed version) fan on my XP-120. At full RPM (1700rpm, ~70CFM), it is reasonably quiet and it keeps my 4400+ plenty cool.

 

[cronic]

i am using a panaflo m1a and it works great roughly 100cfm. i also tried a delta 190 cfm. it did lower the temp 1-3 degrees but it was MUCH louder, and not worth it to me.

 

[BonzaiDuck]

I tried to scan through most of the posts to avoid being redundant.

I spent a lot of time trying to find the "right" fan for my XP120. Consider that more air molecules per second or per minute means greater air velocity, and less time available for any molecules passing through the heatsink fins to absorb heat from them. So there is an upper limit to the CFMs and therefore (roughly) fan RPMs in their impact on CPU temperature reduction.

I used several fans, including a 120x38mm Sunon (108CFM -- max), a 120x25 mm Silverstone (104CFM max), and a thermally-controlled Delta Tri-blade (142 CFM max.) I finally got wise and ran the tri-blade off the CPU_FAN plug -- the 0.8 Amp maximum draw of the fan was something like 0.02 Amp more than the average amperage draw recommended for any of the three fan plugs, and just a tad more than a third of the total draw recommend for all plugs combined. I controlled the Delta fan with Almico's SpeedFan.

A rock-bottom load temperature was achieved at about 119 CFM if you could accurately estimate CFM from fan speed. That is, if 142 CFM occurs at the fan's top speed of 3,700 rpm, then 3000 rpm would push approximately 115 CFM through the heatsink fins. After that, there was no additional cooling effect -- just more noise.

 

[Vegitto]

Originally posted by: BonzaiDuck
I tried to scan through most of the posts to avoid being redundant.

I spent a lot of time trying to find the "right" fan for my XP120. Consider that more air molecules per second or per minute means greater air velocity, and less time available for any molecules passing through the heatsink fins to absorb heat from them. So there is an upper limit to the CFMs and therefore (roughly) fan RPMs in their impact on CPU temperature reduction.

I used several fans, including a 120x38mm Sunon (108CFM -- max), a 120x25 mm Silverstone (104CFM max), and a thermally-controlled Delta Tri-blade (142 CFM max.) I finally got wise and ran the tri-blade off the CPU_FAN plug -- the 0.8 Amp maximum draw of the fan was something like 0.02 Amp more than the average amperage draw recommended for any of the three fan plugs, and just a tad more than a third of the total draw recommend for all plugs combined. I controlled the Delta fan with Almico's SpeedFan.

A rock-bottom load temperature was achieved at about 119 CFM if you could accurately estimate CFM from fan speed. That is, if 142 CFM occurs at the fan's top speed of 3,700 rpm, then 3000 rpm would push approximately 115 CFM through the heatsink fins. After that, there was no additional cooling effect -- just more noise.

So you're saying that anything more than 120 CFM is not benifitable?

 

[Cerb]

Originally posted by: Vegitto
How much CFM will an XP-120 benefit from? I mean, is there some kind of overkill on an XP-120? After how much CFM will you no longer see a benefit? 100 CFM? 120? 150? 200?

Enough to reach its minimal thermal resiatnce, which I believe is around 0.16ºC/W. Basing that on fans is hard to do. A fan's CFm rating is based on free air, not on a heatsink. A fan that can deal with high static pressure will give better actual CFM on the HS.

 

[bwanaaa]

I am thinking of the silverstone too. It's advertised as a case fan but has a speed conroller and is thinner rthan the 38 mm variety of fan allowing for more airflow to it. In any event, I drilld a 120 mm hole above the fan to get fresh outside air to the cpu so that's not an issue. BUT QUIET IS.

 

[Vegitto]

BUMP.

 

[BonzaiDuck]

Vegitto wrote:

"So you're saying that anything more than 120 CFM is not benifitable? "

_________________

Yeah, that seems to be the case. I see someone else is familiar with the thermal resistance rating of the XP-120. Actually, and more precisely, it is supposed to be 0.167.

I couldn't get a tighter spread between idle and load temperatures with CFM above 120. It would draw some criticism where I may have suggested that you could "estimate" an approximate CFM for different rpm speeds based on the top-end speed and the rated top-end fan CFM. I think it is a reasonable assumption that there is some linearity in that relationship.

But to dispel more complicating speculation and exchange -- at 142 CFM -- the rated top-end throughput for my Delta Tri-Blade -- the load temperature was essentially the same as it was when I let the fan run around 2,800 or 3,000 -- top-end being 3,700. Although I didn't record the results, there was only a slight improvement with the Delta in the 2,800-to-3,000 range over a Sunon (108CFM top-end at 3,200) and a Silverstone (104CFM at top-end of around 2,750). My CFM "estimate" for the Delta Tri-Blade in the above-mentioned range was about 119 or 120 CFM.

Fan weight is also a consideration for the XP120. The 120x38mm fans can range in weight between 192 gm ( a YS-Tech) to something like 250 gm (a Panaflo H1 model -- maybe it was an M1). As light as the YS-Tech fan was, I think it had a rated throughput of 118 CFM or something, it was "over-rated." The Sunon provided better cooling and its throughput rating was only 108 CFM.

And then, you can worry about noise. But the fan-ratings in dBA are for the top-end speed. So a fan generating 50 dBA at 3,800 rpm might show noise less than 40 at-- say -- 2,800 or 2,500. If you get adequate cooling under idle or modest CPU loads with the fan spinning at 2,500, and you can thermally variate the fan-speed according to the CPU thermal sensor (as with Almico's SpeedFan software) -- who cares if it gets noisy occasionally while gaming yourself to pieces? Tune up your 5.1 speakers, and I guarantee while blowing away the monsters in Doom 3, you won't hear the damn CPU fan.

 

[BonzaiDuck]

One more observation. There is ONE significant advantage to blowing more air through the XP120 than what is required to reach best thermal resistance and minimum load temperature.

It really helps with your chipset heatsink and memory modules, especially if you do some motherboard ducting.