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Corsair 800d. Rads as intake or exhaust?

post #1 of 3
Thread Starter 
I have a 360 rad on top currently as exhaust. I also have two aio coolers cooling my gpu's. One on the back as exhaust and one on the bottom as intake. Which way would be the best way to run them?

Ideally it would be better to have them all intake air from outside the case but then I would have no exhaust. I have a 5.25 bay mount fan ordered for intake that should arrive next week.

I recently added some corsair sp 120's to the top rad for extra performance but for some reason my gpu temps went up when I did. Doesn't make sense to me. Ambient temps have gone up here recently so that may have something to do with it.
post #2 of 3
Ideally, you'd want to have intake on the bottom and exhaust fans on the top of the case, as hot air rises.
post #3 of 3

I went through the same issue some time back. I am going to repost it here from my post on HardOCP.

 

 

The Obsidian 800D is a full-featured full-tower PC case that is very popular amongst us. The case has many advanced features, but one of the most advertised (by Corsair) is the three isolated cooling zones . The aim of this post is to share with you some theory and my results with the 800D as it relates to air cooling and positive/negative pressure configurations.

Every time I walk into MicroCenter I seem to buy something my wife thinks I do not need, little does she know (keep separate credit cards gentlemen ). I am a sucker for large cases and so rather expectedly a Corsair 800D magically made it into my office to replace a relatively “smaller” Coolermaster Stacker 832. 

Once the rebuild was complete my new rig had emerged. An overclocked 4.2 Ghz Intel Core i7 with two GTX 480s SLI in tow, I was quiet pleased, until the stress testing began.
After several moments of denial I eventually came to accept the simple truth that my new $280 enclosure sucked  (my wife seemed pleased with my suffering). My Coolermaster Stacker sat laughing in the corner, it was a venerable air cooling god compared to the 800D. Not to be defeated, I began down this path and figured I would share my findings.

METHODS AND STUFF:
Equipment:
Motherboard: Asus P6X58D Premium @ stock chipset voltages.
CPU: Intel Core i7 930 Overclocked @ 4.2 Ghz @ 1.35/1.35V
Cooler: Corsair H50 on rear exhaust using a 120-140mm adapter
Memory: Corsair Dominator DDR3-1600 Mhz (7-7-7-18) @ 1.75V
GPU: Nvidia GTX 480 SLI Overclocked: 850 / 2100 @ 1.125 V (Fan 100% @ 80C)
Hard Drive: Intel X25-G2 SSD and WD RE2 500 GB x 3 RAID 0
Power Supply: Coolermaster UCP 1100
Fans: Stock Corsair 140mm, Yate Loon140mm, Panaflo 120x38mm and 92x25mm.

Software: 
Everest Ultimate Edition (5.00.1650)
MSI Afterburner 2.1.0
BOINC (6.10.58)

Other:
Cheap Oregon digital thermometer
Elijah Craig 18 year bourbon

Idle measurements were recorded after 30 minutes. Load measurements were recorded after 60 minutes of CPU/GPU/RAM abuse using BOINC. All equipment was verified stable in prior Coolermaster Stacker enclosure using multiple protocols including Prime 95, LinX, and OCCT. 

STOCK: Epic Air Cool Fail!
The stock Corsair 800D is a neutralish pressure design that favors a quiet computing experience over performance. 



There are low rpm 140mm fans at the base, over the hard drive cage, and at the rear. The overall air path is simple and elegant. The stock fans are stupid quiet, almost inaudible. They are also stupid slow; spinning at around ~1000rpm they move very little air. Fine for some, but hardly for the average enthusiast, bent on overclocking their hardware.


The stock case performed so badly that I terminated the load test early when my CPU passed 80+ C and my GPUs were past 100 C. Hard drives seemed happy though .

Room: 22 / 22 C
Board: 35 / 45 C
CPU: 48 / 85 C - FAIL
GPU 1: 65 / 105 C - FAIL
GPU 2: 58 / 100 C
HDD: 33 / 40 C

REPLACE STOCK FANS: Replace fans, maintain air path and neutral pressure. 
I replaced the stock intake and exhaust fans with Yate Loon D14SH-12 140mm fans. They spin at around 1800 rpm and supposedly push ~100 cfm. The website says they do 2800 rpm, maybe there is a new model or I got robbed , $8 - who cares. The stock Corsair drive cage fan remained in place.

There was an immediate and substantial improvement. The CPU temps came back into range and would stabilize. However, the GPU remained an issue . The GTX 480 is a notoriously hot card, exponentially worse when overclocked, and nearly demonic when in an adjacent SLI configuration. This was going to be a challenge.

This configuration would run indefinitely when the CPU was loaded. It would quickly fail when the GPUs were loaded. 

Room: 22 / 22 C
Board: 30 / 35 C
CPU: 44 / 75 C
GPU 1: 60 / 105 C - FAIL
GPU 2: 52 / 100 C
HDD: 33 / 36 C

EXHAUST FANS: Added exhaust fans, changed air path, slight negative pressure bias.


I left the Yate Loon 140mm bottom intake fan and stock Corsair drive cage fan in place. I reversed the rear Yate Loon 140 mm exhaust fan to intake (Corsair H50) and added three Panaflow 120x38mm exhaust fans to the roof. The Panaflo spin at around 1700 rpm and push at least 70 cfm at 30 dB. That makes ~200 cfm of intake and ~210 cfm of exhaust, at least by the numbers, not taking into account the GTX 480 exhaust.

There was another incremental improvement over simply replacing the stock fans. The tremendous exhaust out of the top of the case was impressive and no hot spots could be found inside the case. The reversal of the rear fan resulted in lower CPU temps. The GPUs were happy at stock clocks, and even when mildly overclocked to 800 Mhz, but that wasn’t the point. I would not be satisfied until I at least matched what was a trivial accomplishment in the Stacker.

Room: 22 / 22 C
Board: 28 / 34 C
CPU: 40 / 69 C
GPU 1: 55 / 105 C - FAIL
GPU 2: 48 / 100 C
HDD: 33 / 35 C

Frustrated, I stayed with this configuration for several weeks. Eventually the negative pressure bias resulted in a bit of dust accumulation around the bottom of the case and on the H50 radiator. I grudgingly cleaned the case out but did not have the motivation to change the fan configuration again. 

Then I was reading an article about the Silverstone Raven series 

The vertical orientation was lauded for its ability to keep the GPU cool. But I also noted that there is a large positive pressure bias, helping force air both through and around the stock GPU heatsinks. If it s good enough for Falcon Northwest, why not me? I cleaned the case out one more time and decided to try something “crazy”. 

INTAKE, INTAKE, INTAKE: Going positive pressure, physics be damned!


I reversed the three 120x38mm Panaflo on top to intakes. I rereversed the rear 140mm Yate Loon to exhaust. I left the bottom 140mm Yate Loon and stock 140mm Corsair drive cage fan as intakes. I removed the PCI slot covers in all the unused slots. Holy positive pressure bat man! This results in 310+ cfm intake and 100 cfm + gpu output as exhaust. I knew I was on to something as the air coming out of the back of the video cards and through the unused slots was significant to say the least.

Room: 24 / 24 C
Board: 25 / 26 C
CPU: 39 / 69 C
GPU 1: 45 / 95 C
GPU 2: 41 / 90 C
HDD: 33 / 34 C

Now that’s progress. This configuration nearly matched my Coolermaster Stacker. It allows for full stable overclocks on both the CPU and GPUs. I ran this setup through several days of gaming and encoding, no problem. This was a preliminary setup as the noise was a bit more than I wanted and there would eventually be piles of dust in the case due to unfiltered intakes at the top. I proceeded to refine the configuration.

FINAL CONFIGURATION: Less is more!


The new setup was a bit loud for my taste so I gutted some old 120mm fans and used them as spacers on the top Panaflo intakes to help decrease intake turbulence (works). I removed the bottom 140mm Yate Loon fan intake completely. I placed a 92mm Panaflo fan (50 cfm @ 2800 rpm) on the front of the video cards. I temporarily removed the stock panel filter from the bottom of the case and placed it on top to filter the intake air (Free). I got some Silverstone vented slot covers for the empty card spaces($7). I then purchased some acoustic pyramid foam and lined the bottom of the case ($10). I also blocked the top rear perforations with closed cell foam to help force air through the video cards and rear/bottom perforations (Free).








Final results:
Room: 24 / 24 C
Board: 25 / 26 C
CPU: 39 / 69 C
GPU 1: 44 / 90 C
GPU 2: 40 / 82 C
HDD: 33 / 34 C

I have gone to a 750D since then and use the same sort of setup with an H110 and two San Ace 140mm fans pulling in fresh air from above. Has worked out great with good positive pressure helping expel air out the video cards and the added benefit of running cooler air over the motherboard VRMS.

 


Edited by RushiMP - 3/2/14 at 2:09am
Titan
(16 items)
 
Apollo
(16 items)
 
CPUMotherboardGraphicsRAM
AMD Ryzen 1800X Asus Crosshair VI AMD Vega FE G.Skill TridentZ 3600 
Hard DriveCoolingOSMonitor
Samsung 960 Pro NVME Corsair H110 with Noctua PPC 140 Fans Windows 10 NEC P402 
MonitorMonitorKeyboardPower
NEC P402 NEC P402 Steelseries Corsair AX1500 
CaseMouseMouse PadAudio
Corsair Obsidian 650D + SGI Fuel Case Mod Logitech G700 Deskpad XXXXL Logitech Z906 
CPUMotherboardGraphicsGraphics
Ryzen 1800X Asus Crosshair VI XFX RX460 XFX RX460 
RAMHard DriveCoolingOS
G.Skill TridentZ DDR4-3600  Samsung 960 Pro NVMe Scythe Ninja 4 Windows 7 
MonitorMonitorMonitorKeyboard
Barco 21 MDRC-2120 Coronis Fusion 6MP LED MDCC-6230 Barco 21 MDRC-2120 Logitech MK710 
PowerCaseMouseMouse Pad
Seasonic X-660 SGI Octane Mod Logitech G700 Deskpad XXXL 
  hide details  
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Titan
(16 items)
 
Apollo
(16 items)
 
CPUMotherboardGraphicsRAM
AMD Ryzen 1800X Asus Crosshair VI AMD Vega FE G.Skill TridentZ 3600 
Hard DriveCoolingOSMonitor
Samsung 960 Pro NVME Corsair H110 with Noctua PPC 140 Fans Windows 10 NEC P402 
MonitorMonitorKeyboardPower
NEC P402 NEC P402 Steelseries Corsair AX1500 
CaseMouseMouse PadAudio
Corsair Obsidian 650D + SGI Fuel Case Mod Logitech G700 Deskpad XXXXL Logitech Z906 
CPUMotherboardGraphicsGraphics
Ryzen 1800X Asus Crosshair VI XFX RX460 XFX RX460 
RAMHard DriveCoolingOS
G.Skill TridentZ DDR4-3600  Samsung 960 Pro NVMe Scythe Ninja 4 Windows 7 
MonitorMonitorMonitorKeyboard
Barco 21 MDRC-2120 Coronis Fusion 6MP LED MDCC-6230 Barco 21 MDRC-2120 Logitech MK710 
PowerCaseMouseMouse Pad
Seasonic X-660 SGI Octane Mod Logitech G700 Deskpad XXXL 
  hide details  
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