Matters of simple physics

[jonnyGURU]

Originally posted by: Fullmetal Chocobo
Hmmm. I never thought about robbing the air of my PSUs. I'll get some pics together for a later post...

Yeah. I actually knew one guy that swapped out three Enermax Liberty's because he thought the fans in them were reversed. He gave up on Enermax and went with a louder FSP unit which didn't seem to have a reversed fan.

I had never heard of such a problem before (not on three different units that likely came from different production runs,) so I asked him to bring me the last Enermax (which he hadn't RMA'd yet) and I set it on the bench and fired it up. I placed a Kleenex tissue over the fan and it blew up in the air.

When I looked at his case later that night, I found a radiator mounted to the back of the case that blocked more than 1/3rd of the PSU fan and a 120MM fan mounted to that that was moving at least 65CFM. I'm fairly certain the Enermax fan doesn't move anymore than 30 to 35CFM.

 

[Zap]

jonnyGURU = perhaps the only person better suited to answer PSU questions than GalvanizedYankee around here.

 

[GalvanizedYankee]

Originally posted by: Syzzi
Thanks a lot for your replies people and for your advice GalvanizedYankee. I can't always buy the same models over here you guys can in the US, but I learnt a lot more than I thought I would when I created the thread

"same models over here"

PLEASE enable your profile so members can serve you better. No need to hide out here.

...Galvanized

 

[Syzzi]

Originally posted by: jonnyGURU
You're worried about a noisy HSF or PSU, but have a case with four fans?

They're all slow 120mm ones, so are all sub-30dba. They wery qwiet

Originally posted by: jonnyGURU
The side panel should not have a fan. Only a vent over the CPU. There should also be a vent below the GPU of your video card. This makes the case TAC compliant.

I'm quite surprised as I saw on Anandtech a few days ago a case with a side panel which could hold 4 120mms! I guess that's bad? Happy to remove my side fan and get even quieter if it'll make things better!

Originally posted by: jonnyGURU
There's nothing wrong with a "chimney" fan on top, but I am curious to see how it's supposed to exhaust when there's a PSU in the way.

It's intake, not exhaust, but if that's bad I could just take it out and leave it as a passive vent.

Originally posted by: jonnyGURU
Yes, a Seasonic S12 has one intake 120MM that sucks air in off of the bottom. And like I said, if you have an exhaust fan mounted in the case directly below that that moves more air than the PSU fan, you'll shorten the life of your PSU.

Hopefully the slowness of the case fan will avoid that problem?

EDIT: Sorry about that Yankee, I didn't realise it was turned off! I'm in the UK btw.

 

[jonnyGURU]

Originally posted by: Syzzi

Originally posted by: jonnyGURU
The side panel should not have a fan. Only a vent over the CPU. There should also be a vent below the GPU of your video card. This makes the case TAC compliant.

I'm quite surprised as I saw on Anandtech a few days ago a case with a side panel which could hold 4 120mms! I guess that's bad?

Originally posted by: jonnyGURU
There's nothing wrong with a "chimney" fan on top, but I am curious to see how it's supposed to exhaust when there's a PSU in the way.

It's intake, not exhaust, but if that's bad I could just take it out and leave it as a passive vent.

Yes. A case with fans in the side panel is bad.

And if the top fan is an intake, that's bad too. Heat rises. Why would you push air down into a case?

Air flow is good, but when you have fans that defeat each other, all you're doing is creating noise.

Are you still not willing/able to provide a link to the case?

I'd say look at a fan from a company that's known to design cases with proper thermaldynamics like Antec, Chieftec, Inwin, Lian-Li, Ultra, Enlight, CoolerMaster, CaseTek, etc.

I would say Thermaltake, but they get a little carried away w/ the fans too.

 

[Fullmetal Chocobo]

Okay, this is the PSU side of my machine. The four fans in the bank push air from the front of the case to the rear. There is a 120mm fan at the top (on both the mobo & PSU sides) for exhaust. The PSUs are Seasonics with the single 120mm fan. Right now, the bank of four fans is off, so I leave the side panel off. When the side panel is on, I will leave the fans on low (just under 7 volts. All four fans are Nidec 92x25mm fans). Do you think there is going to be a problem with airflow in this case? I could install a fan in the side panel for intake near the PSUs if necessary.

A pic of the front of the case. The air flow in the front isn't the greatest I guess. There are 1.5" vents goin down the side panel of the case that are right before the banks of fans on both the right and left side. That is the intake side of the case, if it matters.

I've been through a lot of Enermax PSUs, hence my current dual PSU config, and I wonder if the airflow / heat might have been a problem in the past. Can't do much about it now, but it's nice to find out what might have been the problem (they were in a different case, by the way).

 

[Syzzi]

Sorry, the case I saw was the Coolermaster Stacker 830. My own case is a rather old inherited one and I'm not even sure who made it as there's not a name on it anywhere. Not helpful I know, but the fans in the case don't really worry me and I'm doing ok in terms of heat. However, your point about the exhaust stealing from the PSU is a good one although it's not a monster so I think it'll be ok.

I know it's a bit of a tangent but I'd be interested to hear, if you had that Stacker 830 case, how you'd arrange the fans in it?

 

[GalvanizedYankee]

Search this forum for Stacker 830. IIRC the 830 has a front door but the Stacker 810 is doorless. Good case. They got good feed back.


...Galvanized

 

[jonnyGURU]

Originally posted by: Fullmetal Chocobo
Okay, this is the PSU side of my machine. The four fans in the bank push air from the front of the case to the rear. There is a 120mm fan at the top (on both the mobo & PSU sides) for exhaust. The PSUs are Seasonics with the single 120mm fan. Right now, the bank of four fans is off, so I leave the side panel off. When the side panel is on, I will leave the fans on low (just under 7 volts. All four fans are Nidec 92x25mm fans). Do you think there is going to be a problem with airflow in this case? I could install a fan in the side panel for intake near the PSUs if necessary.

I've used cases like that in the past... and also have left the middle fans off. They're supposed to move the air from front to back, but only end up whipping the air around and making noise.

Where's the 120MM fan in the front? Usually there's a 120MM behind three of the 5.25" bays, isn't there?

 

[jonnyGURU]

Originally posted by: Syzzi

Originally posted by: jonnyGURU
You're worried about a noisy HSF or PSU, but have a case with four fans?

They're all slow 120mm ones, so are all sub-30dba. They wery qwiet

Originally posted by: jonnyGURU
The side panel should not have a fan. Only a vent over the CPU. There should also be a vent below the GPU of your video card. This makes the case TAC compliant.

I'm quite surprised as I saw on Anandtech a few days ago a case with a side panel which could hold 4 120mms! I guess that's bad? Happy to remove my side fan and get even quieter if it'll make things better!

I know that case and it's a toss up for me. Obviously adding fans to the side panel is going to add noise. That's where you have to find the balance. Having fans bring air in like that isn't bad cooling, but all you have between you and those fans is a mesh screen. The only cooling problem you run into there is that the side panel fans defeat the front fan, so the hard drives end up running hot.

Originally posted by: Syzzi

Originally posted by: jonnyGURU
There's nothing wrong with a "chimney" fan on top, but I am curious to see how it's supposed to exhaust when there's a PSU in the way.

It's intake, not exhaust, but if that's bad I could just take it out and leave it as a passive vent.

Are you sure it was supposed to be installed that way? Any case I've worked with in the past; lower front is intake while uppper rear is exhaust.

Originally posted by: Syzzi

Originally posted by: jonnyGURU
Yes, a Seasonic S12 has one intake 120MM that sucks air in off of the bottom. And like I said, if you have an exhaust fan mounted in the case directly below that that moves more air than the PSU fan, you'll shorten the life of your PSU.

Hopefully the slowness of the case fan will avoid that problem?

It might. As long as cool air is getting into the case. That's the major concern. Negative pressure sucking the air away from the intake of the power supply.

 

[Howard]

Originally posted by: jonnyGURU

Originally posted by: Syzzi

Originally posted by: jonnyGURU
The side panel should not have a fan. Only a vent over the CPU. There should also be a vent below the GPU of your video card. This makes the case TAC compliant.

I'm quite surprised as I saw on Anandtech a few days ago a case with a side panel which could hold 4 120mms! I guess that's bad?

Originally posted by: jonnyGURU
There's nothing wrong with a "chimney" fan on top, but I am curious to see how it's supposed to exhaust when there's a PSU in the way.

It's intake, not exhaust, but if that's bad I could just take it out and leave it as a passive vent.

Yes. A case with fans in the side panel is bad.

And if the top fan is an intake, that's bad too. Heat rises. Why would you push air down into a case?

I ask myself that every time I look at the Silentium PSU.

 

[Fullmetal Chocobo]

Originally posted by: jonnyGURU

Originally posted by: Fullmetal Chocobo
Okay, this is the PSU side of my machine. The four fans in the bank push air from the front of the case to the rear. There is a 120mm fan at the top (on both the mobo & PSU sides) for exhaust. The PSUs are Seasonics with the single 120mm fan. Right now, the bank of four fans is off, so I leave the side panel off. When the side panel is on, I will leave the fans on low (just under 7 volts. All four fans are Nidec 92x25mm fans). Do you think there is going to be a problem with airflow in this case? I could install a fan in the side panel for intake near the PSUs if necessary.

I've used cases like that in the past... and also have left the middle fans off. They're supposed to move the air from front to back, but only end up whipping the air around and making noise.

Where's the 120MM fan in the front? Usually there's a 120MM behind three of the 5.25" bays, isn't there?

No front 120mm fans. There are 4 92mm fans on the right bank, 4 92mm fans on the left bank, 1 120mm fan in the back on each side, the two processor fans, and the two hd enclosures each have a 92mm fan there. The left and right bank of fans sits behind the 5.25" enclosures on each side. They are normally hot swappable, but I changed out the fans and as such, they are no longer hot swappable.

 

[jonnyGURU]

Fans hanging inside the case and mounted to hard drives and the like don't really do much for cooling in my opinion. You still have to get air into the case. Otherwise, you're just moving air around.

 

[JEDIYoda]

Originally posted by: Zap
jonnyGURU = perhaps the only person better suited to answer PSU questions than GalvanizedYankee around here.

I hope you cashed the check real fast...lol

 

[Fullmetal Chocobo]

Originally posted by: jonnyGURU
Fans hanging inside the case and mounted to hard drives and the like don't really do much for cooling in my opinion. You still have to get air into the case. Otherwise, you're just moving air around.

Hmm. This is the SATA enclosure. It has a fan mounted on the back on the enclosure to pull air across the hds. The case temps aren't too bad. But what do you think as far as getting air to the PSUs? You think they are good?

 

[jonnyGURU]

I'm familiar with those. Half the servers I built last year were Supermicro chassis.

But they don't help the case temps if they don't pull air in.

But if you say case temps are good, c'est la vie. I'd like a 120MM up front somewhere and all of those internal fans out IMHO.

 

[Fullmetal Chocobo]

Originally posted by: jonnyGURU
I'm familiar with those. Half the servers I built last year were Supermicro chassis.

But they don't help the case temps if they don't pull air in.

But if you say case temps are good, c'est la vie. I'd like a 120MM up front somewhere and all of those internal fans out IMHO.

I'm not too keen of the mid-case fan modules either. But I'm working with them as much as I can. I will either end up putting intake fans on the mobo side later, or putting a fan on the side panel and diverting air over the CPU HSFs. But what do you think about the PSU cooling condition. There is a lot of ambient space on the PSU side, so I wouldn't think that they would be starving for air. That might have been the situation for the previous cases though.

 

[jonnyGURU]

You're right. The case is roomy enough, I'm sure the PSU's are getting plenty of air down there.

 

[sodcha0s]

Heat doesn't naturally go sideways does it?

Heat ALWAYS travels from a warmer to a cooler place. Heat itself does not "rise." Warm air rises because it's less dense than cool air, but that can be easily remedied with a fan...
I see the "heat rises" statement constantly and it is completely false, and it makes me crazy!