Go Back   nV News Forums > Hardware Forums > General Hardware

Newegg Daily Deals

Reply
 
Thread Tools
Old 01-27-08, 08:01 PM   #13
XDanger
Whaaat?
 
XDanger's Avatar
 
Join Date: Nov 2005
Posts: 5,728
Default Re: Positive pressure vs negative for cooling

once again I say dry ice in a paper cup ftw
__________________
2500K 4.7ghz,P8P67Pro,120gb Force3, 8gb Vengeance,R9290,TX850v2,W7HP,LaCie Blue 22" crt COMMODORE 64 Silver Label 1Mhz/128D 4Mhz(Z80)
XDanger is offline   Reply With Quote
Old 01-28-08, 01:49 AM   #14
BCKator
Registered User
 
Join Date: Aug 2006
Location: San Diego CA
Posts: 135
Default Re: Positive pressure vs negative for cooling

I don't understand why people say positive=good negative=bad=dust. If you're not filtering your inputs then you will get dust, whether pushed in or pulled in. Now, I filter all of my inputs so I only want air getting into my case via these inputs so I run a slight positive pressure (so that I don't pull unfiltered air in via the cracks). I also try to close up gaps w/ tape and foam to eliminate un-wanted flows. As was said before, you want to move as much air through the case as possible so exhaust fans help. I also use ducts and foam inserts to limit the amount of "dead" air pockets and force the flow of air over the components to be cooled and force known hot air (from CPU/GPU/FETs) directly out of the case as much as possible. Restricting airflow is OK so long as you are restricting it to move over the things to be cooled. I try to only use quieter 120mm fans and fit as many as possible. I run at 5v under idle conditions (so noise is not an issue) and raise to ~10.5v as required via thermal-based fan control.
__________________
"BlackSilver": Modified air-cooled LianLi8B w/ 4 38x120mm Scythe intake fans, 16"x16" custom air filter, custom fan controller, GIGABYTE GA-P55M-UD4 (uATX), i5-750 @3.5G(turbo)OCCT linpack stable, 4G GSkill DDR, XFX 5870, Crucial 128GB SSD (OS), WD 1T CavBLack HD (data), WD 2T Green HD (backup), Corsiar CMPSU 750W PSU, PWR ~105/370W idle/max

"Green" : AsusP5Q-E, C2D8600@~4.4G(440Mx10), EVGA GTX285@~741/1692/1269, 300G Velocirator + 150G Raptorx (just for show), DVD-RW, custom H2O loop w/ Koolance CPU/GPU/NB/FET blocks in heavily modified LianLi case w/ 16"x16" input air filter, integrated 3x120 swiftech rad, dual mcp350 pumps, lots of copper pipe, custom Fan controller, & 7 Scythe SFF21F fans (~600rpm@idle, ~1400rpm@load), PWR ~160/484W idle/max.
BCKator is offline   Reply With Quote
Old 01-28-08, 03:50 AM   #15
Slammin
Registered User
 
Join Date: Oct 2004
Posts: 1,123
Default Re: Positive pressure vs negative for cooling

I think it mostly depends on the case. Some cases do better with positive (usually the ones with an exhaust blowhole at the top), and some cases (like Antec Sonata) do better with negative, probably due to the vented side panel.

If positive causes hot spots, try negative, but i always go for slightly positive when I can get away with it.
__________________
Abit IN9 32x MAX- Kentsfield QX6700 @3520
1.5 vcore watercooled D-Tek Fuzion/PA-160/MCR120/2x MCP655
2x2GB G-Skill 1066 5-5-5-15 2T@1.9vdimm
2x EVGA 580GTX 1.5GB Sli
2x 74GB Sata Raptor Raid0
2x 320GB Hitachi Sata II
X-FI Elite Pro
Dell U3011
Lian Li V2100B
Corsair HX1000
Slammin is offline   Reply With Quote
Old 01-28-08, 02:42 PM   #16
XDanger
Whaaat?
 
XDanger's Avatar
 
Join Date: Nov 2005
Posts: 5,728
Default Re: Positive pressure vs negative for cooling

Not pulling out enough can let the dust settle, Is that what this + / - stuff is all about?
__________________
2500K 4.7ghz,P8P67Pro,120gb Force3, 8gb Vengeance,R9290,TX850v2,W7HP,LaCie Blue 22" crt COMMODORE 64 Silver Label 1Mhz/128D 4Mhz(Z80)
XDanger is offline   Reply With Quote
Old 01-28-08, 06:00 PM   #17
Libertysyclone
I Lie about MPG
 
Libertysyclone's Avatar
 
Join Date: Jun 2007
Location: SL,UT
Posts: 531
Send a message via MSN to Libertysyclone
Default Re: Positive pressure vs negative for cooling

I have a 250mm in the front pushing into the case and a single 120mm in the rear pulling. I have VERY LITTLE dust issues in a unfinished basement.

I think people get WAY TOO crazy with fans. I have a Q6600 @3.6Ghz (stock cooler) 3 HDDs one being a raptor 4x1gb sticks of Ram, Razer Sound Card, 8800Ultra, Tesla C870. in my case and the hottest the CPU gets is mid 60's same with the GPU.

Hottest HDD is the Raptor X @ 25*C
Ram is slightly warm to the touch.

I think Volume has a lot more to do with cooling than the amount of fans.

Cliff Notes: Get the biggest case you can.
__________________
System=
Q6600@3.8Ghz/ EVGA 790i Ultra/ EVGA 9800GX2/ and some H20
Libertysyclone is offline   Reply With Quote
Old 01-29-08, 01:07 AM   #18
mullet
 
mullet's Avatar
 
Join Date: Oct 2005
Posts: 8,069
Default Re: Positive pressure vs negative for cooling

Quote:
Originally Posted by Libertysyclone
I have a 250mm in the front pushing into the case and a single 120mm in the rear pulling. I have VERY LITTLE dust issues in a unfinished basement.

I think people get WAY TOO crazy with fans. I have a Q6600 @3.6Ghz (stock cooler) 3 HDDs one being a raptor 4x1gb sticks of Ram, Razer Sound Card, 8800Ultra, Tesla C870. in my case and the hottest the CPU gets is mid 60's same with the GPU.

Hottest HDD is the Raptor X @ 25*C
Ram is slightly warm to the touch.

I think Volume has a lot more to do with cooling than the amount of fans.

Cliff Notes: Get the biggest case you can.

+1
__________________
• LIAN-LI PC-A70B • ASUS MAXIMUS V FORMULA (0701) • i7-3770k + NOCTUA|NH-D14 • Intel 520 240GB SSD • G.SKILL Ripjaws X Series 16GB DDR3 1600 •
• EVGA GeForce GTX 680 • PCP&C 750 Quad • ASUS BD-ROM • DELL U2711 H-IPS + DELL 2209WA e-IPS• Windows 7 Pro x64 SP1 • Logitech Z5500 5.1 •
mullet is offline   Reply With Quote
Old 01-29-08, 01:45 AM   #19
einstein_314
w00t!!
 
einstein_314's Avatar
 
Join Date: Dec 2003
Location: Victoria, BC
Posts: 2,905
Default Re: Positive pressure vs negative for cooling

I don't know about the biggest case idea. I'm currently in 3rd year mechanical engineering and have taken a few thermodynamics courses. Here's my thoughts.

First off, air is a terrible heat conductor. It sucks. So for good heat transfer out of your case, you need a high flow rate of air through it. You want that air moving relatively fast.

As for positive pressure vs negative pressure, ideally you would have a neutral pressure, that would reduce the load on the fans and you would get the fastest air flow out of them. I honestly don't think it makes that much of a difference though, at least from a cooling point of view. I tend to do positive pressure though. I find it keeps the dust down inside the case.

Libertyscyclone: Your comment about biggest volume I don't think is very good. I don't think having more volume in your case will improve cooling. Sure if you had more fans as well it might, but just increasing the volume shouldn't increase heat transfer. If anything it will just increase the number of dead air zones and you'll have hot pockets.

I think the best way to improve cooling is clean up your cables and have a nice stream of air flow from the front of the case to the back.
__________________
Intel Core 2 Quad Q6600 @ 3.2GHz (9 x 355) w/ Swiftec APOGEE GTX Waterblock|| Asus P5B-Deluxe WiFi Edition
eVGA 8800 GTX Superclocked Edition @ 675/1150 w/ DangerDen 8800GTX Waterblock|| 4x1GB Mushkin XP2 PC2-8500
X-Fi Fatal1ty 64MB || PC Power & Cooling Silencer 750W || Seagate 7200.10 320 GB || Dell 2407WFP
Logitech Z-5300 Speakers || Sennheiser HD555's || Logitech G7 || Logitech G15 || Windows Vista Ultimate x64
einstein_314 is offline   Reply With Quote
Old 01-29-08, 09:42 AM   #20
Riptide
Registered User
 
Join Date: Oct 2002
Location: Billings, MT
Posts: 8,303
Default Re: Positive pressure vs negative for cooling

What do you guys think of the Lian Li PC80?
http://www.newegg.com/Product/Produc...82E16811112159

Very nice yes? Lots of volume. But $400??
Riptide is offline   Reply With Quote

Old 01-29-08, 11:44 AM   #21
mullet
 
mullet's Avatar
 
Join Date: Oct 2005
Posts: 8,069
Default Re: Positive pressure vs negative for cooling

Rip my case is based of that design and its only 239.00, with tons of room. water cooling room/PSU top or bottom........
http://www.newegg.com/Product/Produc...82E16811112141
http://www.nvnews.net/vbulletin/show...12&postcount=9
__________________
• LIAN-LI PC-A70B • ASUS MAXIMUS V FORMULA (0701) • i7-3770k + NOCTUA|NH-D14 • Intel 520 240GB SSD • G.SKILL Ripjaws X Series 16GB DDR3 1600 •
• EVGA GeForce GTX 680 • PCP&C 750 Quad • ASUS BD-ROM • DELL U2711 H-IPS + DELL 2209WA e-IPS• Windows 7 Pro x64 SP1 • Logitech Z5500 5.1 •
mullet is offline   Reply With Quote
Old 01-31-08, 04:25 PM   #22
Libertysyclone
I Lie about MPG
 
Libertysyclone's Avatar
 
Join Date: Jun 2007
Location: SL,UT
Posts: 531
Send a message via MSN to Libertysyclone
Default Re: Positive pressure vs negative for cooling

Einstein_314; I agree with you I do think that you need to size fans per case and that there are dead spots, but I think a bigger case has better options I direct air it my case a few different ways, and I have great cable management.

Here is an older pic of my case. It now has the water cooling setup and a 120mm in the rear but air flow is still the same.

Same setup that I was 3.6Ghz stable on the stock Intel cooler.

I lowered my 5.25 res to direct the air from the inlet fan towards the mobo.

I have never seen the Raptor get over 25*C

My Ultra is in the 50's under load when the Tesla C870 is not in the case.

My only other plan is to get another 120mm and make a tube/shroud for the RAM/Chipset.

Also all my unused back expansion slots dont have covers/ I think this tends to make a neutral pressure which also makes fans more quite.

CPU/GPU temps go up 5-8*C with the side panel off.

__________________
System=
Q6600@3.8Ghz/ EVGA 790i Ultra/ EVGA 9800GX2/ and some H20
Libertysyclone is offline   Reply With Quote
Old 01-31-08, 06:13 PM   #23
Riptide
Registered User
 
Join Date: Oct 2002
Location: Billings, MT
Posts: 8,303
Default Re: Positive pressure vs negative for cooling

mullet I like that case and noticed it earlier. Seems like the extra 120mm cooling fans behind the hard disc drive cage in the lower front part might cut into the extra space you gain from the depth of the case. Still more room than my Tsunami though.
Riptide is offline   Reply With Quote
Old 02-01-08, 01:37 AM   #24
mullet
 
mullet's Avatar
 
Join Date: Oct 2005
Posts: 8,069
Default Re: Positive pressure vs negative for cooling

Yeah, I don't like the stock HD cages case manufactures make at all. They put a cage in the bottom front and by the time you put HD's in there the 120mm fan or 2 120mm fans have been blocked to where there is about no air flow at all. I know my case is huge inside but I am really happy with the fan configuration and flow. I can't wait to see the temps of say a Q9450 or maybe a E8400 with a T-UE120 compared to my E6600 and the Thermalright Ultima-90.

BTW Libertysyclone nice setup dude.
__________________
• LIAN-LI PC-A70B • ASUS MAXIMUS V FORMULA (0701) • i7-3770k + NOCTUA|NH-D14 • Intel 520 240GB SSD • G.SKILL Ripjaws X Series 16GB DDR3 1600 •
• EVGA GeForce GTX 680 • PCP&C 750 Quad • ASUS BD-ROM • DELL U2711 H-IPS + DELL 2209WA e-IPS• Windows 7 Pro x64 SP1 • Logitech Z5500 5.1 •
mullet is offline   Reply With Quote
Reply


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 09:47 AM.


Powered by vBulletin® Version 3.7.1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©1998 - 2014, nV News.