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Mofset (I think)

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July 31, 2012 1:01:11 PM

Hi,
Currently running 3930 @ 4.5Ghz at 1.36v

after 1 hour latest version prime 95 CPU 77c and other temps look fine according to sensors.

I have one question regarding this picture



The twelve square blocks in from of the blue heatsink - what are they. Ran a temp guage after 2 hrs prime 95 and they were over 100c

I've added a fan pointed directly at them which has dropped it to about 95c.

What are these components? Should I heatsink them? Are they conductive? I mean can I just run one heatsink straight across or do I need 12 small individual ones.

Any help much appreciated


Thanks


Mick

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a b V Motherboard
August 1, 2012 2:16:20 AM

Probably no need Vcore so high to 1.36V, you can down it to 1.3V around and test again.
And running Prime95 with your configuration, it must require a water cooling fan system .. such as Corsair H100 is fairly good to get 85C around during Prime98 small FFT test to tight your cpu up.
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a c 170 V Motherboard
August 1, 2012 3:04:33 AM

Those are the voltage regulators. The voltage regulator is a switching buck converter which is used to take a 12 volt supply from your PSU (which has its own switching components inside of it) and step it down to the VCore specified by the VID or through manual configuration.

The VRM works by turning those MOSFETs on and off at varying rates. Transistors are most electrically efficient when they are passing either no current (off) or passing the most current. Anywhere in the middle is inefficient and results in a lot of waste heat.

The VRM turns the MOSFET on and allows current to flow from the 12 volt supply through the transistor, through an inductor (which just filters out the high frequency transient effects from the switching), and simultaneously to the CPU and a capacitor. The charge on the capacitor will build up over time which increases the voltage across the capacitor. As the voltage builds up it is fed into a feedback loop which is used to control the amount of time that the MOSFET is on and off (duty cycle). Without the feedback loop the charge would continue to build up on the capacitor and VCore would eventually reach 12 volts. This is why the vcore fluctuates a bit, the VRM is constantly lagging ever so slightly behind changes in the CPU's impedance, trying to keep VCore steady.

If the capacitor isn't large enough, or isn't of high quality then a sudden change in load impedance will drain the capacitor before the feedback loop can allow more current through the switching transistor. This is characteristic of multiple core processors and highly overclocked processors, they draw a lot more current and thus require beefier power delivery.

So the natural solution is to put a large number of these switching circuits in parallel which is where the 4/8/12/16/20 phase VRM idea comes from. By putting them together the capacitance of each phase is added, this allows for the CPU to draw more current and have a higher current slope without distrupting the supply voltage as much.

EDIT: to answer your question. No they are not conductive on the top but much of the material below is. You can put a heat sink on them if you'd like, just don't use conductive paste.
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August 9, 2012 10:33:38 AM

Thank for the info guys.

BeryLee - I've tried lower voltage usiing offest and just can't get it stable. Highest temps with my H100 water are about 80-82c (onlty one core - the rest stay low-mid-70s)

Pinhedd - Is it worth cooling these or am I just wasting my time?

Thanks

Mick
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a c 170 V Motherboard
August 9, 2012 12:15:17 PM

Cooling them will extend the lifespan if they're running significantly hotter than they were designed for. On a gigabyte board I would suspect that this is the case
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August 10, 2012 10:33:24 PM

Thanks for the info - I measure them at 120c. I've gotten them down to about 100c by placing a couple of Antec spot fans pointed in their direction.

Thinking of maybe placing some small heatsinks.
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a c 170 V Motherboard
August 10, 2012 11:43:05 PM

mikeytjames said:
Thanks for the info - I measure them at 120c. I've gotten them down to about 100c by placing a couple of Antec spot fans pointed in their direction.

Thinking of maybe placing some small heatsinks.


you can get RAM heatsinks for a reasonable price at most PC shops and they will fit well
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August 11, 2012 3:17:27 AM

Best answer selected by mikeytjames.
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a c 328 V Motherboard
August 11, 2012 4:31:19 AM

This topic has been closed by Nikorr
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