Hello Friends,
I have some very important information for you all today. My own personal theory stated on the bottom of Page 6 on the Official SNDS thread has been quite confirmed. Intel even says the Heatsink is an antenna that can greatly effect the CPU.
We know why SNDS occurs, but their are so many variables that it is hard to debug the true reason. Why do some die even when their temp is low, some die when the temp is low and voltage is stock, some die when both are high. One thing in common with all 3 is much higher frequencies and EMI increases. We know voltage can kill a processor, we know heat kills, we know over frequencies cause Electro migration, we can also assume that the processor was not made as good as the ones in last months batch, and so on and so on.
The one thing we have very little control over is the EMI's, radiation and frequencies. So today with a little help from a search engine I was able to find some very interesting documentation provided by a data sheet. Section 2.3 Heatsink Effects: http://www.intel.com/design/pentiumii/applnots/24333402.PDF
"As the processor’s core frequency increases, so does the opportunity for its heatsink to act as a radiating antenna. Studies have shown that its size, geometry, and orientation have an effect on the amount of emissions generated. While Intel cannot recommend which heatsink to use and what orientation is best, as it is system dependent, the designer should consider heatsink effects and determine the best solution for their particular system.
Experiments have also suggested that grounding the processor’s heatsink may reduce emissions. Creating a ground path from the heatsink to either the motherboard or chassis ground will return
some stray current to its source and reduce EMI. While this may have both positive and negative effects on various frequencies, the decision is again left to the system designer on the implementation and whether it has a positive effect on passing regulations.
Other items of note are the thermal interface material (between the processor and heatsink) and the distance of the heatsink to the processor core. Experiments have shown that the distance of the processor heatsink to its core can greatly have an effect on emissions. Since the heatsink acts as an antenna, the amount of processor noise coupled to the heatsink is relative to the distance between the two. A thermal interface material can reduce EMI by helping to prevent the heatsink from getting too close to the processor."
My thinking is... YOU MAY WANT TO HIGHLY CONSIDER USING 'STANDARD WHITE LONG LASTING NONCONDUCTIVE THERMAL PASTE'. YOU MAY ALSO WANT TO GROUND YOUR HEATSINKS TO YOUR CASE.
Take care, Brian
I have some very important information for you all today. My own personal theory stated on the bottom of Page 6 on the Official SNDS thread has been quite confirmed. Intel even says the Heatsink is an antenna that can greatly effect the CPU.
We know why SNDS occurs, but their are so many variables that it is hard to debug the true reason. Why do some die even when their temp is low, some die when the temp is low and voltage is stock, some die when both are high. One thing in common with all 3 is much higher frequencies and EMI increases. We know voltage can kill a processor, we know heat kills, we know over frequencies cause Electro migration, we can also assume that the processor was not made as good as the ones in last months batch, and so on and so on.
The one thing we have very little control over is the EMI's, radiation and frequencies. So today with a little help from a search engine I was able to find some very interesting documentation provided by a data sheet. Section 2.3 Heatsink Effects: http://www.intel.com/design/pentiumii/applnots/24333402.PDF
"As the processor’s core frequency increases, so does the opportunity for its heatsink to act as a radiating antenna. Studies have shown that its size, geometry, and orientation have an effect on the amount of emissions generated. While Intel cannot recommend which heatsink to use and what orientation is best, as it is system dependent, the designer should consider heatsink effects and determine the best solution for their particular system.
Experiments have also suggested that grounding the processor’s heatsink may reduce emissions. Creating a ground path from the heatsink to either the motherboard or chassis ground will return
some stray current to its source and reduce EMI. While this may have both positive and negative effects on various frequencies, the decision is again left to the system designer on the implementation and whether it has a positive effect on passing regulations.
Other items of note are the thermal interface material (between the processor and heatsink) and the distance of the heatsink to the processor core. Experiments have shown that the distance of the processor heatsink to its core can greatly have an effect on emissions. Since the heatsink acts as an antenna, the amount of processor noise coupled to the heatsink is relative to the distance between the two. A thermal interface material can reduce EMI by helping to prevent the heatsink from getting too close to the processor."
My thinking is... YOU MAY WANT TO HIGHLY CONSIDER USING 'STANDARD WHITE LONG LASTING NONCONDUCTIVE THERMAL PASTE'. YOU MAY ALSO WANT TO GROUND YOUR HEATSINKS TO YOUR CASE.
Take care, Brian
