picked up a NZXT Sentry 2 for cheap, should I keep it?

Control: management of fans, temp/rpm monitoring via soft/hardware

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IDvsEGO
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picked up a NZXT Sentry 2 for cheap, should I keep it?

Post by IDvsEGO » Mon Apr 26, 2010 12:48 pm

My local frys had these for $20 and a $10 rebate for a net price of $10. I want to control my 3 case fans and ideally my zalman 9500 CPU fan. is this good for that? Also wondering if I will have any problems with my projected upgrade path of the Xigmatek s1283 and Slip Stream or YL fans.

BlackWhizz
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Post by BlackWhizz » Mon Apr 26, 2010 12:56 pm

If you like it keep it :P

NXZT is a quality brand. Volt range looks good also.

IDvsEGO
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Post by IDvsEGO » Mon Apr 26, 2010 1:08 pm

cool, thats what I wasn't too sure about it. I had no knowledge just wanted to grab it before they were all gone. I actually just decided today that I even wanted to add a controller.

themaster1
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Post by themaster1 » Mon Apr 26, 2010 11:30 pm

You can't control your CPU fan with it it don't support the PWM function (assuming the fan is a 4-pin) as i wrote in another topic. Nevertheless, it's an excellent fan controller with a vivid touch screen viewable from all angles, at first there is a beep when you press it but you can disable that.

IDvsEGO
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Post by IDvsEGO » Tue Apr 27, 2010 5:16 am

I am trying to decide how important the cpu fan control is to me. Master, I saw your link to the zalman controller but am having a harder time finding a place to buy it for a reasonable price. I was hoping to stay around $20ish. If I cant do the PWM control or CPU control for that I will use the sentry 2 and just mount the little zalman individual controller where I can reach it.

as I am looking at other cotnrollers, how can I tell if it has PWM support?

IDvsEGO
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Post by IDvsEGO » Tue Apr 27, 2010 5:57 am

So i Just did some more reading and I feel like such a noob. Its been a long time since i actually put thought into my computers. so, the PWM feature allows the motherboard to control the fan speed based on the bios temp readings. I am actually ok with that so I don't feel like I need the CPU fan on the controller. Now I am back to just the case fans. that means this little sentry 2 should be just fine.

themaster1
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Post by themaster1 » Tue Apr 27, 2010 6:45 am

IDvsEGO wrote: so, the PWM feature allows the motherboard to control the fan speed based on the bios temp readings.
That's my understanding aswell hence the 4th pin the which provide infos to the mobo and in return that good mobo regulate the rounds per minute accordingly.Regular fans have 2 or 3 pins (= no PWM) unless you use an adaptator (??). Anyway, to give you an example the fan for my cpu is a Noctua NF-S14 FLX 120mm 3 pin. I have connected it to my mobo on the 4pin plug and it's working like a charm at 600 rpm all the time. Very quiet.All the others fans i have (about 3 or 4) are controlled with the sentry 2.

ascl
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Post by ascl » Tue Apr 27, 2010 3:32 pm

Many motherboards do support CPU fan control with 3 pin fans (the mobo's actually typically use PWM to do this... but thats another story). There are definite advantages to some kind of dynamic fan speed control (be it in the bios or software ala speedfan), and some disadvantages.

The pins for fans are:
2 pin:
earth + 12v

3 pin: earth + 12v + sense

4 pin : earth + 12v + sense + control

With the 4 pin version, the 12v is constant, and the control line sends a signal to the fan to tell it what frequency to sample the 12v line at (effectively reducing the amount of power going to the fan and hence its speed).

3 pin fans are controlled by adjusting the 12v line, either by reducing the voltage (ie a rheostat style fan controller), or by adjusting the pulses of 12v sent (ie a PWM style fan controller with 3 pin fan support).


Hope this helps clarify.

lodestar
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Post by lodestar » Wed Apr 28, 2010 6:12 am

IDvsEGO wrote:so, the PWM feature allows the motherboard to control the fan speed based on the bios temp readings.
Strictly no it doesn't. Multi-core CPUs have two sets of temperature sensors. There is one mounted on the CPU which reports a generic CPU temp, and there are Digital Thermal Sensors mounted on each core which report core temps. PWM works off the core temps. The alternative to PWM - voltage control - works off the CPU temp, and is the only method available if a three pin fan is used. CPU temp is also what is shown in the BIOS.

Now on the face of it, this would not seem to matter - two systems, same outcome? But it does matter because the core temp reading are always higher than the CPU temp reading by at least 4-5C, and maybe more. And because not all cores are loaded in the same way one or more cores may be much hotter than other cores. PWM fan control will deal with this, but voltage control is hampered by relying on a generic reading taken outside of the CPU cores.

The easiest way of seeing the two sets of CPU temperature readings is through something like HWMonitor, the basic version is a free download from http://www.cpuid.com/hwmonitor.php.

IDvsEGO
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Post by IDvsEGO » Wed Apr 28, 2010 7:23 am

I have been monitoring my core temps for a while now so that I can see if the heatsink changes make any sizable difference in heat levels. thanks for the extra details.

ascl
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Post by ascl » Wed Apr 28, 2010 12:52 pm

lodestar wrote: PWM works off the core temps. The alternative to PWM - voltage control - works off the CPU temp,
Have you got a reference for this? It seems (from a programming/software point of view) an odd distinction to make.

lodestar
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Post by lodestar » Wed Apr 28, 2010 1:41 pm

This is from http://www.intel.com/cd/channel/reselle ... /index.htm

"....Digital Thermal Sensor (DTS) Provides for more efficient processor and platform thermal control, improving system acoustics. The DTS continuously measures the temperature at each processing core. The ability to continuously measure and detect variations in processor temperature enables system fans to spin only as fast as needed to cool the system. The combination of these technologies can result in significantly lower noise emissions from the PC....".

Edit: And from http://www.intel.com/Assets/en_US/PDF/d ... 318675.pdf

"....PWM (Pulse Width Modulation also synonymous with Pulse Duration Modulation PDM) is a modulation in which the duration of pulse is varied in accordance with some characteristic of the modulating signal. This solution is being offered to help provide better control over pedestal chassis acoustics. This is achieved though accurate measurement of processor temperature through the processor’s Digital Thermal Sensor (DTS) temperature. Fan RPM is modulated through the use of an ASIC (Application Specific Integrated Circuit) located on the serverboard, that sends out a PWM control signal to the 4th pin of the connector labeled as Control.

This heatsink solution also requires a constant +12 V supplied to pin 2 and does not support variable voltage control or 3-pin PWM control. If no PWM signal is detected on the 4th pin this heatsink solution will revert back to thermistor control mode, supporting both the 4-wire PWM and standard 3-wire ambient air control methods...."
Last edited by lodestar on Wed Apr 28, 2010 1:54 pm, edited 2 times in total.

ascl
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Post by ascl » Wed Apr 28, 2010 1:47 pm

Thats not saying that PWM is based on Core Temp and voltage control is based on CPU temp tho. It doesn't make any sense to base 2 different control methods on different sensors when trying to achieve the same thing. If you use something like Gigabytes SmartFan software to change the fan settings, it only uses CPU temp (as in the bios), regardless of the type of fan you use.

Anyway, we are pretty OT I think! :)

lodestar
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Post by lodestar » Wed Apr 28, 2010 2:00 pm

ascl wrote:Thats not saying that PWM is based on Core Temp and voltage control is based on CPU temp tho.
I have edited the previous post to include a reference that confirms that non-PWM fans use a generic temperature sensor, and not DTS. And as you say, this may be getting a bit too techy for some. But I would still recommend any multi-core processor user to install HWMonitor and look at the readings, to find out what is actually going on with their CPU temperatures.

ascl
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Post by ascl » Wed Apr 28, 2010 2:38 pm

No arguments about HWMonitor, its a great app, and the author is very responsive to suggestions and bug reports (at least if you are a paid user anyway).

Thanks for the links! Very interesting. I am still not convinced that selecting voltage control vs PWM control for the fan changes which sensors are used (especially as "voltage control" typically uses PWM to alter the voltage sent to the fan -- ie the PWM logic is on the motherboard rather than the fan, but the same method is used).

As always, discussions on this forum are mature and educational :)

ascl
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Post by ascl » Sun May 02, 2010 1:19 pm

So being the generally curious person I am, I took this up with a Gigabyte rep, and asked him about it. He said, type of fan makes no difference, they both respond to the same sensor. He also said, that he was pretty sure (but not certain) that the sensor they reacted to was the core temps, not the CPU temp.

Not sure it really makes any practical difference, but I thought it was interesting :)

lodestar
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Post by lodestar » Mon May 03, 2010 4:41 am

The Gigabyte rep should try using their own hardware. I am one of the people who used to buy Gigabyte, still have a Gigabyte system in fact but switched to Asus. A major reason was that BIOS fan control options were so limited, Gigabyte seemingly taking the attitude that PWM was an on/off function and nothing more. I also found that Gigabyte persist in providing only one PWM header on a motherboard together with that strange four pin, but not PWM header. This might have been alright five or six years ago, but when it comes to BIOS fan control Gigabyte have stood still. Compare this with for example Asus who offer four different PWM modes for the CPU header on their current motherboards, and in some cases two different PWM modes for the chassis PWM header.

So Gigabyte's attitude that PWM and three pin fan control are just two sides of the same coin does not surprise me, nor for that matter does the lack of awareness of how Intel's chipsets work.

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