Need a new PC, but not sure of best option

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beowuuf
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Re: Need a new PC, but not sure of best option

Post by beowuuf »

Well, as a power supply company guy, I'm not going to give you a definitive idea :p


Basically you are trying either blow or pull cold air across your fins, and get rid of the hotter air from your tower in favour of pulling cold air in (through the fan or from the other side of the case from your fan)

As long as you have good flow as a push or pull system in your case, I wouldn't worry too much.
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

What? ;-)

Not sure I've explained things properly. This is the recommended setup I've seen nearly everywhere -- blue is cool air being sucked into the case, red is as it gets warmed up:

Image

Here's a mockup of what would be happening in my setup with the CPU cooler rotated. Surely blowing extra heated air into the PSU fan isn't a good idea?

Image
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Re: Need a new PC, but not sure of best option

Post by zoom »

I think the 2 vents will add up, thus creating a twice as strong current, therefore the extra heat will be negligible.
Your CPU cooler will be cooler in the 2nd pic than in the first pic, and vice versa for the powersupply.

not too sure , though. BUt if you look at pic 1, then you see that the entrance air of the power supply is not very cold to begin with!(it gets partly air from the cpu cooler´s exit anyways)

the critical part is that the vents work!

(some guy would argue with a friend of mine whether or not to have the fent blow air into the cassis (and not out).
the logic: cold air gets blown inside from the outside, that would have a better or same cooling effect .. oh well.
I think it is common knowledge that the warm air has to get out of there, or not?
To the defence of that man, at first it is not that clear: why not reverse? I would like, if any notions here, to hear opinions on the reversal of vents .But it is not needed. thanks)
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

I created these pictures: the colours are notional and not accurately representative of how hot or cold the air is :-)

How can the PSU be cooler in the second pic if I'm blowing extra warm air into it?

This is the exact case i bought. There is no fan anywhere on the front of the machine that is blowing cool air into the chassis, so it's all coming from the sucked in air from the rear fan and the fans on the cpu and psu. There's an optional side fan that can be added to increase the suction within the chassis.

Forgive me if I'm being ignorant about this, but I don't seem to be able to get a straight answer about this anywhere and it's driving me nuts!
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Re: Need a new PC, but not sure of best option

Post by beowuuf »

Sorry, your set up is basically the same - just go for it!

I thought you meant your fan was the opposite way around on both the case and CPU.

There is no real difference in what you have here. Both have your case fan sucking out hot air, and both have your CPU fan pushing air across the chip. Neither are a worry.

There is also no difference between the hot air being upwards or sideways.
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

So blowing extra hot air over an already hot PSU is not a problem? This seems to go against everything I've read. Confused!
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Re: Need a new PC, but not sure of best option

Post by beowuuf »

What extra hot air? The two layouts you've shown me don't seem to have much in the way of extra heat between each other. You are either blowing the air sideways then sucking it up into your PSU, or you are blowing it upwards then sucking it up into your PSU. In both cases the same amount of ambiant air has to come from the front at the same rate of flow.
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

I was under the impression that the setup in (1) above creates a "tunnel" effect, with the rear case fan being strong enough to help extract the warm air coming off the CPU heatsink -- rather than it being sucked into the PSU. I thought the PSU fan was more for cooling the PSU itself, not extracting hot air from the rest of the case? I guess I simply don't understand how this works!

I don't know.... for some reason I just feel really nervous about installing the CPU heatsink+fan into a sub-optimal position. It's so massive and new and shiny and I don't want to mess it all up with thermal paste and all that shit if it's not actually the best way to mount it. But if you're sure it doesn't make any difference.... ?
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Re: Need a new PC, but not sure of best option

Post by Chaos-Shaman »

Gambit37 wrote:I was under the impression that the setup in (1) above creates a "tunnel" effect, with the rear case fan being strong enough to help extract the warm air coming off the CPU heatsink -- rather than it being sucked into the PSU. I thought the PSU fan was more for cooling the PSU itself, not extracting hot air from the rest of the case? I guess I simply don't understand how this works!

I don't know.... for some reason I just feel really nervous about installing the CPU heatsink+fan into a sub-optimal position. It's so massive and new and shiny and I don't want to mess it all up with thermal paste and all that shit if it's not actually the best way to mount it. But if you're sure it doesn't make any difference.... ?
hehehehehe, don't worry about it gambit, unless you have had an overheating problem in the past system setups. probably will work fine without a fan, hehehehe
don't worry, just need to give it a breeze... :)
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Re: Need a new PC, but not sure of best option

Post by Sophia »

Chaos-Shaman wrote:unless you have had an overheating problem in the past system setups.
It depends on how much in the past. It seems like every generation of computers have bigger heat problems.
Chaos-Shaman wrote:probably will work fine without a fan
No, it really is essential! A modern CPU will overheat quite rapidly without a fan.
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Re: Need a new PC, but not sure of best option

Post by Joramun »

My cousin just bought a new laptop for 400-500 bucks.
It's high-end, with 1400*900 res on a small 10-12'' screen.
It's more powerful than my 16.5'' laptop,
which has overheating problems any time I start a 3d game
(which makes Conflux and DSB quite a pleasure to play).
What Is Your Quest ?
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Re: Need a new PC, but not sure of best option

Post by beowuuf »

Sophia wrote:No, it really is essential! A modern CPU will overheat quite rapidly without a fan.
And a power supply will die pretty quickly qithout a fan too - I had to replace by previous PSU when the fan died. And my laptop was the same when the PSU fan died. Good news, the power supply otherwise worked after it overheated and my lap[top still works. Modern computers are good at killing themselves off if they look like overheating.
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Re: Need a new PC, but not sure of best option

Post by Jan »

Poor old Gambit. :( :wink:

As BW, I don't see much difference between the two layouts. Perhaps, I will try to have as strong rear fan as possible to get enough air into the system, and I will try to make sure there's enough space for the air to get from the CPU fan to the PSU.

Is there any way to measure the temperature of PSU?

Fingers crossed! :wink:
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

Aargh. On other forums, some have said "You don't want an updraft into the PSU, you want a crossdraft." Others have said it doesn't matter. Still others have said completely different things.

I just want somebody who knows about this stuff to say unequivocally and unambiguously: "It doesn't matter if you blow the hot air from the CPU heatsink directly into the PSU."

Can someone actually say that please to put my mind at rest? :)
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Re: Need a new PC, but not sure of best option

Post by T0Mi »

2 pictures:
You likely won't notice much of a difference between these 2 setups. Or at least none that can be measured with the on-board devices.

2 fans in a row:
generally this won't increase the mass flow, at best the possible pressure gain will increase. In a casual setup, you won't see any temperature drop at all. (This is what I experienced while overclocking my old PC, trying to get rid of the hot air with a double fan.)
This may change as soon as the cooler gets plugged with dirt (increasing the pressure drop).

pull/push:
As been said: you likely won't see much difference. However, depending on the initial design of fan and cooler (push/pull) the aerodynamic efficiency will differ, and thus the sound output as well as the rpm needed to keep the temperature at the same level. Also the turbulence intensity of the fluid withhin the cooler is likely higher for the push case (thinner boundary layer), which can result in a higher heat transfer rate. But likely all of this will be hard to recognize at all.
the critical part is that the vents work!
This is what it is all about. Be sure to have the warnings active. You can also set the fans at a constant low rpm, which is more comfortable than a fan that comes to life (at much higher rpm) from time to time. You'll also quickly notice something is wrong if you don't recognize the typical noise booting the PC.

All in all: don't worry. It will work just fine.


EDIT:
I just want somebody who knows about this stuff to say unequivocally and unambiguously: "It doesn't matter if you blow the hot air from the CPU heatsink directly into the PSU."
I won't claim to know much about setting up a PC or aerodynamics in general (in fact, calculating the coefficients of a porous region, leaves me avoiding solving a simple square deviation, instead setting up a simulation solely for getting them iteratively). Still I would say: a PSU is a sturdy piece of electronic, designed to withstand ambient temperatures of 60 degrees and more. It won't do any harm if you blow the 'hot' air from the CPU into the casing of the PSU.
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Re: Need a new PC, but not sure of best option

Post by zoom »

I have not read or heard about a crash of a machine due to the built shown on 2nd pic.
You should place the pc not too close to a wall, for the air to flow unhindered out of the chassis. So look for a good place to put your tower. That is,
enough space around it, to draw air from and blow it out again.

To be 200% sure ;) read about your processor specifics. Does it overheat quickly, are there safety mechanisms?
Of course there are.
In the worst case : IF the pc is destroyed, you have still guarantee on it! Backup your work on a regular basis, and the rest is life. Do not try to prepare for all eventualities. If something bad happens, you did all you could. God or whatever will take care of it, let it flow.
BUILD the nice , new and shiny machine together and get going!! YEEAAH!!!
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

Thanks guys :) I know I'm obsessing about something that probably seems inconsequential to the rest of you. I can't help it, sorry ;)

I had this incident with my doctor the other day:

"Hi doc, I have this lump in my chest, what is it?"
"Let's see." (prods around a bit) "OK, it's nothing to worry about."
"Er. OK. But what is it I'm not supposed to be worried about?"
"It's nothing, don't worry about it!"
"But it wasn't there before. Something must have caused it. What is it?"
"Oh right. You're one of those. OK, well, this is what it is...."

I'm the kind of person who needs exact, specific answers before I'm satisfied. Saying "it doesn't make a lot of difference" doesn't satisfy someone like me. Sorry if I annoyed anyone. :)
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Re: Need a new PC, but not sure of best option

Post by Chaos-Shaman »

not at all gambit37, i understand how hard it is. like i said, my son and i bought a new pc each. they are identical in every way. took months to find the parts i liked. I bought a tower that had a large fan on its side to keep the case cool. i've bought 11 computers so far and not one of them overheated. my daughter bought her own laptop, it overheats on her. i told her not to leave it on her bed and bought a matt with two fans to fix her problem. only the computer hard drives have ever given out on me. i think you will be just fine with either way gambit37. you can always buy a fan for the case. it looks like you can add a fan on the front back side panel, not sure. as for the mysterious lump, oh man, get 2cd and 3rd opinions!!!
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

The lump is fine, it's something to do with my xihpoid process and is very common. The point I was making is that he wouldn't have told me this if I hadn't continued to question him. Many doctors seem to think that saying "don't worry" is enough to get a patient out of their surgery quickly, but for those of us who actually think about things, it just raises more questions!
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Re: Need a new PC, but not sure of best option

Post by zoom »

and now?
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Re: Need a new PC, but not sure of best option

Post by T0Mi »

feeling very much like the elephant (and coders to be humans), but in case it helps:
http://www.youtube.com/watch?v=LgX6mH_HDIs
(switching the direction of a fans' inlet radically)
Don't worry so much.
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Re: Need a new PC, but not sure of best option

Post by sucinum »

Just start your machine up, you have some backups before your CPU melts:

1. Modern CPUs don't use too much power in desktop mode and most of the time, yours will run at half power anyways, since dualcore isn't supported across the bank. So it won't get that hot initially, allowing you to measure the desktop mode temperature and compare it to other values in the internet.
2. Also it takes a while for your case to heat up inside (modern GPUs also have a desktop mode to avoid heating, giving you a lot of extra time), especially if you have a steady airstream inside and your PSU has a powerful fan (same as CPU and GPU, this one also doesn't run at full power most of the time).
3. Before melting, your CPU will shut down itself as protection. And CPUs can get really hot, my old P4 survived temeratures around 80°C.

All this desktop/2D-mode stuff is quite new, my new PC is much cooler than my P4 in desktop mode, so overheating actually got better. :)
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

Without cooling, AMDs last about half a second before exploding! Well, the old ones used to. I can't imagine running one with no cooling on it, but perhaps it's all different with these newer chips...
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Re: Need a new PC, but not sure of best option

Post by Chaos-Shaman »

Gambit37 wrote:Without cooling, AMDs last about half a second before exploding! Well, the old ones used to. I can't imagine running one with no cooling on it, but perhaps it's all different with these newer chips...
i did gambit, and the older cpu did get hot hot hot, but it never stopped working either. i can say i enjoyed the quietness, hehehehe
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Re: Need a new PC, but not sure of best option

Post by beowuuf »

newer chips and PSUs are intelligent, as i told you before this laptop ran without fans for a while ages ago...alway shut down...still here. recently psu fan of new comp stopped working, machine shut down. still working now.

if your config has a problem, it will show a fault without kiling anything
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

Posting this from my new silent PC :-) Talk about making a difference! Can't believe I have put up with that noisy old monster for so long!!!

It's gonna take me a while to set it up though. I downloaded the ATI drivers for the integrated chip, installed, and nothing happened. I'm gonna have to make sure I pay attention to whether stuff is 64 bit or not, this is a whole new ball game for me.

Pretty nice so fa, even though I can't really use it properly for work yet. Still need new software and a new monitor!

I bought 2 x 320GB drives. Windows formatted one of them during install. I'm not sure what I should do regarding the partitions though, or what I should do with the second drive. I was originally going to RAID them but I'm totally confused by how to do that, have read all sorts of conflicting instructions. I'm used to small partitions -- is there any benefit to partioning these drives, or should I just leave them as one big partition?
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

Cocking hell, there's something wrong with this board and/or the ATI drivers. Drivers will install but the driver software won't run. Aarrrghhhh!
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Re: Need a new PC, but not sure of best option

Post by beowuuf »

Have you let windows 7 run an uopdate? You'd be surprised at what their updates have support for.
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Re: Need a new PC, but not sure of best option

Post by Gambit37 »

Looks like a system restore back to the initial installation point. Not entirely sure what's happened but I think I may have installed XP drivers then overwritten them with Win 7 drivers and messed up the whole caboodle. Shit on a stick, imagine what this would be like for non techies!
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Re: Need a new PC, but not sure of best option

Post by beowuuf »

Non-techies would buy a whole machine. You pay the rpice for your techie0ness by requiring techie-ness :D
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