Trying to strike a balance between power headroom and noise

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birthdaymonkey
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Trying to strike a balance between power headroom and noise

Post by birthdaymonkey » Fri Feb 04, 2011 8:55 am

Hi SPCR forums,

This is my first post here so please be gentle.

I've got a Lian Li PC-v351, which is an idiosyncratic case to say the least. It fits really well into my entertainment setup and I love the aesthetics, so I want to keep it. My GF is opposed to a tower case in the middle of our living room, so I'm basically stuck with SFF even though I know it's not ideal for cooling or silence.

If this computer was a simple HTPC, I'd be fine installing some low RPM fans and that would be the end of it. However, this is my only desktop computer (I can't afford another one anytime soon), so it also doubles as a light gaming system, and of course it has to be OC ;)

Specs:
Seasonic M12II 620W
Lian Li PC-V351 (modded slightly to improve 80mm exhaust output)
Phenom II X4 940 @3.5GHz (1.4 volts)
4GB Kingston DDR2
XFX Radeon 6870
Mushkin Callisto Deluxe SSD, WD Green (EARS) 1.5TB

Cooling:
CPU: Noctua U9B-SE2
Intake: 2x Scythe GT 1850RPM 120mm
Exhaust: Noctua NF-R8 80mm
5.25" bay fan controller (connected to all of the above)

At first, my problem was finding a CPU cooler that fit. The U9B just barely squeezed in there, and it does a pretty excellent job compared to the Scythe Big Shuriken I had before. Finding the optimal intake fans has been my most recent obsession. I've use quite a few different fans for intake and found none of them entirely satisfactory.

I need something that operates silently when dialed down (usually for watching movies or listening to music) but has enough oomph to ventilate my OCed CPU and GPU when turned up to max.

Most recently, I've tried a couple different Scythe GT models. At first, I used the 1150rpm ones, but they didn't go fast enough for heavy load cooling. Currently I've got the 1850s in the intake role and they're not bad. My major problem with the GTs seems to be quality variability from fan to fan. I even bought 3 1850s when I only needed 2 because I anticipated this problem based on my experience with the 1150s. Perhaps this is because of the issues I've read about with shipping ball bearing fans, but of the 5 GTs I've bought, 2 (an 1850 and an 1150) have sounded beautiful at both max speed and undervolted. The others (3/5) all make pitch warbling noises (especially at high RPMs) and chatter slightly (the bearings?) all the time. The cooling performance does not appear to be affected, but the noise drives me nuts.

I have a Scythe Kama Flex PWM fan (1600RPM) too, so I decided I would try that in place of the noisy GT 1850. At high speed it's louder, but it seemed to move more air too (judging by the highly scientific hand in front of the fan test with the side panels off the case). However, when I closed my case and fired up Prime95, I found that the cooling performance was not as good as the GT 1850 (CPU and motherboard temps 2-3 degrees hotter) despite the higher airflow and louder noise. At low RPMs, the Kama Flex sounded much better than the noisy GT it replaced, and probably better than my good GT. I'm guessing that the high static pressure of the GTs makes them more suitable for my case, which seems to need a focused beam of air to ventilate the back corners of the strangely laid out chassis.

Now I'm thinking of trying something else as my intakes. Candidates currently being considered are Scythe Slipstreams or S-Flex (but I assume these will be more or less the same as the Kama Flow, ie not as good as the GT1850), and Noctuas (NFP12 or NFS12B, I'm thinking P12 since it seems to have airflow characteristics more similar to the GT). Remember, I need something with high power that undervolts well and moves air efficiently to the back of my cube case. Or should I play the GT lottery again and order more 1850s hoping one of them makes it to me without quality issues?

I really enjoy tinkering with the cooling in my system, but dealing with this intake fan issue is still frustrating. One day I'll have a dedicated HTPC in this case and move my main operations to a tower case with better airflow, but if anyone can help me improve the status quo, I would really appreciate it.

Thanks for reading my novel!

MikeC
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Re: Trying to strike a balance between power headroom and no

Post by MikeC » Fri Feb 04, 2011 4:31 pm

It's an entertaining and insightful novel. 8) So far... will have to see how it ends. ;)

I can't help thinking... surely you could improve cooling by enlarging the intake vents somehow.

frenchie
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Re: Trying to strike a balance between power headroom and no

Post by frenchie » Fri Feb 04, 2011 4:44 pm

Welcome to SPCR ! :mrgreen:
Have you considered Nexus fans as well ?

ces
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Re: Trying to strike a balance between power headroom and no

Post by ces » Fri Feb 04, 2011 8:07 pm

I have the Lian Li PC-v351 as well, so I understand your pain.

1. The dual 1850s are about as good as you are going to get. You can dial them up or down to whatever you need.

I am running two 1200 rpm Slipstreams at I think 10v. I also put some filterright filters in front of them to stop the dust (http://www.performance-pcs.com/catalog/ ... ts_id=2275) They do fit in there.

This is a high static pressure application. I would expect most fans to generate higher airflow than the Gentle Typhoons when run in open air. I don't believe that any other generally available computer fans can match them under high static pressure though. Apparently that is what your test confirmed.

2. I am using a normal Shuriken. I hate it.

3. "(modded slightly to improve 80mm exhaust output)" I cut out the grating. Is that what you did? I also turned the fan around so the air goes in instead of out. I also replaced the stock fan with a 80mm kamaflex (SA0825FDB125L)

4. Seems to me you are getting distracted by a red herring. You are probably getting enough airflow in and out of the case. If it is your CPU temps that are bothering you focus on the cooling the CPU. If it is your graphics card, that is a little more complicated.

5. CPU. I think the new Noctua downdraft with one fan will fit into 105mm. Drill some extra holes and flip your PSU upside down to avoid aerodynamic conflict. That will take care of your CPU just fine.

6. Video Card. Remove the GT aimed at your card and replace it with the directional 120mm Silverstone fan. If that doesn't get fresh air to your video card, nothing will. Nexus also has an air straightener device you could try as well. It will fit, you just need to buy some extra long bolts at the local hardware store.

ces
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Location: US

Re: Trying to strike a balance between power headroom and no

Post by ces » Fri Feb 04, 2011 9:40 pm

1. If the above doesn't work, try a set of one of these along with a controller to turn them up for gaming and back down when not gaming. There is just no substitute for Brute Force.

Scythe Gentle Typhoon 120mm x 25mm Fan - 3000 RPM (D1225C12B7AP-29)
http://www.frozencpu.com/products/12363 ... _Soon.html

Scythe Gentle Typhoon 120mm x 25mm Fan - 5400 RPM (D1225C12BBAP-31)
http://www.frozencpu.com/products/12365 ... =g36c15s60

These high speed GTs have an interesting ring to help direct airflow (and keep the blades from flying apart).

2. Here are the silverstone fans that I mentioned:

Silverstone Air Penetrator AP121 120 x 120 x 25mm Fan - UV Blue Blades (SST-AP121)

Take a look at the Youtube demo here:
http://www.frozencpu.com/products/11259 ... =g36c15s60

3. Here is the Nexus 120mm Beamair Fan Gril

http://www.nexustechnologyusa.com/c/ntu ... amair.html

tim851
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Re: Trying to strike a balance between power headroom and no

Post by tim851 » Sat Feb 05, 2011 4:03 am

What are the temps?
You mentioned they got worse with the Kama's, but not how much.

And why would you say the v351 is weirdly laid out? The two intake fans are in a perfect position to blow air across all of the mainboard. The layout is actually quite perfect. But there aren't any real intake vents. Those strips at the bottom front and at the bottom are pathetic.
I doubt it's gonna get any better than the Gentle Typhoons where airflow at high impedance is concerned.

In a case with such limited cooling, an overclocked Phenom X4 is really a gutsy move ;)

birthdaymonkey
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Location: New Brunswick

Re: Trying to strike a balance between power headroom and no

Post by birthdaymonkey » Sat Feb 05, 2011 11:49 am

Wow, thank you all for the feedback.

As for the mod, yeah I cut away the rear fan grille and replaced it with a much less restrictive wire fan guard. I didn't reverse the direction of the fan though... Ces, did you realize a benefit from doing this? It would seem to go against the general cooling principles of intake and exhaust... unless you switched the front fans to exhaust. I guess some people use a positive pressure strategy, though I've never tried it.

Those high RPM typhoons look pretty cool. I wonder how well they undervolt? My concern with those would be the price vs. the apparent risk of damage in shipping. (Remember, I've bought five GTs and only two of them seem to have made it to me unscathed.) I'd be looking at some serious cash for two of those 3000RPM GTs once I had them shipped to Canada... although I must admit they're tempting.

My temps right now are mostly within tolerances. With all the fans turned up, I ran Prime95 for seven hours yesterday and my max core temps were 59 degrees (avg. 56-57), with the motherboard CPU temp sensor registering a few degrees cooler. When I swapped in the Kama Flex in place of the noisy GT, the CPU temps got up to 60 quite quickly and the motherboard temp was reading around 35, when it's usually 30-32 with two GTs. I used to have the CPU at 3.6 GHz (1.45 volts), but I backed off to 3.5 GHz (1.4 volts, might try 1.375 and see if it's stable) because the 940 really starts to become a voltage pig after 3.5 (people often report 1.55volts to get it up to 3.8... serious case of diminishing returns). Even at 1.45, core temps didn't get above 62, but when I ran OCCT GPU test + Prime95 at the same time for about an hour, the temps got out of hand (65-66 core and the case was radiating heat like a space heater). The overclocked 940 is definitely ballsy for this case, hehe. The C2 stepping Phenoms run notoriously hot even compared the C3s, but I just couldn't resist the deal with newegg had them on for $99 (the 955 C3s were going for $150 at the time).

I'd like to have the airflow to be able to run GPU and CPU at max and have the temps stable. I considered the top-down Noctua (the C12P I think?) that Ces mentioned, but it was more expensive than the U9B and I'd read about people having issues with it fighting the PSU for air. I never considered flipping the PSU and drilling new holes, although I wish I had at the time... probably not going to shell out $80 for a new HSF after spending $60 not that long ago.

I like the GT 1850s and love the V351, don't get me wrong. I just wish I had better luck with consistency on the GTs I've ordered. If I could be guaranteed that they'd sound as good as my perfect samples, I'd probably just order another 1850, or even one of the 3000s. The bad 1850s irritate me because of the pitch variation sound and chatter, even when they're dialed down. Every time I get to a quiet part in a movie, there they are ...taunting me! Have I just been unlucky with the GTs I've ordered?

At least I've learned from people's responses that other higher flow/lower pressure fans probably aren't going to help. I was ordering a new PSU for my grandfather yesterday, and NCIX has 1900 RPM Slipstreams for $8 apiece, so I ordered two of those to give them a try. I realize they're probably not going to be perfect, but for $16 I figure they're worth a shot ;) I know the Nexuses are highly recommended, but I have a hard time imagining that 1000 rpm fan is going to do much in a high load situation, although they'd no doubt be much more pleasant when I'm using the computer for everyday non-gaming tasks.

I've considered moving the the PC-v354 when it's available in Canada (nobody up here seems to have the black ones in stock yet). It seems to have better airflow and more HD bays than the 351, and I think it would pass the GF approval process.

Wow, this has become even longer than the OP. I think I'm starting to ramble now, so I'll stop. :)

ces
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Location: US

Re: Trying to strike a balance between power headroom and no

Post by ces » Sat Feb 05, 2011 5:31 pm

1. Please let us know now the 1900 RPM Slipstreams work. I don't have any numbers but I don't think the slipstreams do well with static pressure. Newegg has a weekend 20% discounts on fans. I think they ship to Canada. Maybe now is the time to add some fans to your inventory.

2. Why don't you just turn down the overclock and put the fans on a controller. Just turn them up when you need it.

ces
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Re: Trying to strike a balance between power headroom and no

Post by ces » Wed Feb 09, 2011 9:04 am

Take a look at these 2200 rpm Yate Loons from Petras. They probably will generate more static pressure than the slipstreams and they don't cost much either.... and they share a lot of DNA with the SPCR reference fans.

viewtopic.php?f=28&t=61485&p=533147#p533147

birthdaymonkey
Posts: 37
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Location: New Brunswick

Re: Trying to strike a balance between power headroom and no

Post by birthdaymonkey » Sun Feb 20, 2011 12:26 pm

ces wrote:1. Please let us know now the 1900 RPM Slipstreams work. I don't have any numbers but I don't think the slipstreams do well with static pressure. Newegg has a weekend 20% discounts on fans. I think they ship to Canada. Maybe now is the time to add some fans to your inventory.

2. Why don't you just turn down the overclock and put the fans on a controller. Just turn them up when you need it.
Reporting back: I've got the 1900 Slipstreams installed, and so far I'm pretty impressed. They make quite a bit more noise than the 1850 GTs at full blast, but they also move more air. My motherboard temps were a couple degrees cooler under stress test than they were before, although the CPU temp seemed about the same--I think I've reached the point where my HSF is getting plenty of air, so adding more case airflow the mix doesn't do much.

At idle, when I've got the Slipstreams dialed down with my fan controller, they sound better than the GTs. As I mentioned, one of my GTs had a bit of bearing noise, which isn't an issue with the Slipstreams. GTs also make a unique tonal sound, even at low RPM, which annoyed me a little. The Slipstreams don't make any motor or bearing noise when they're turned down, no clicking or chatter either. I can't tell you what voltage they're running at currently, but they're almost silent except for a faint woosh, and they seem to be providing plenty of flow for playing music/video.

Thus, my conclusions: In the "unique" environment of the Lian Li PC-V351, the Slipstream 1900s might offer better bang for the buck than the GT 1850s. The GTs are much quieter at full power, but the Slipstreams provide better airflow at full power. At low power, the Slipstreams are quieter than the GTs while still providing adequate flow.

I've only had them in for a day, so I haven't completely made up might mind about which fans will stay. Right now I'm leaning toward the Slipstreams. At $8 apiece, I think they have the edge over the twice-as-expensive ($15) GTs for my application.

geofelt
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Re: Trying to strike a balance between power headroom and no

Post by geofelt » Wed Apr 20, 2011 10:53 am

Thank you ces and birthday monkey; your discussion was most helpful.
I have a similar problem.
Using a V351, a GTX580, and i5-2600K@4.0 I have heat problems under load.
I used a silenex compact cooler because the Noctua U9B would not fit under the raised grille pf my psu.
I am trying to determine my best course of action.
My motherboard is a Asus P8P67-M PRO. It is nice in that it has 4 speed controlled fan headers.
I think I could replace the lian li front fans to good effect with higher cfm units that would increase speeds while gaming. Is the scythe slipstream 1900 fan still the consensus choice? Would the 1600 unit do enough? Or, is there a better choice. I want it reasonably unobtrusive under desktop use, and it is ok if it gets louder under load.

I think mounting my psu upside down will give me enough room for the Noctua U9B. I was only 1-2mm short.

Was changing out the rear 80mm lian li fan for a 92mm fan helpful?
What did you use for it? It seems to me that Noctua, while good, is a bit expensive.

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