Wire on heatsink?

[HelpTerryPlease]

I purchased 2 used slot 1 cpu's that had huge aluminum heatsinks without fans. There is an insulated wire screwed to each heatsink with a flat 5 pin connector(female) on the end to plug into the motherboard I assume. I would like to know what this wire is for since it obviously is not to power a fan. What purpose would it have? Thanks, Terry

[Beta Geek]

The only thing I can think of is some sort of a built in temperature sensor. Although, only two wires are needed for a thermistor. Is it a single wire leading to a 5-pin connector, or are there 5 wires?

[HelpTerryPlease]

Thanks for the response. There are two wires coming from the heatsink. The screw into the heatsink actually holds a small aluminum plate that the wires are attached to and the wires go into what could indeed be a heat sensor. The two wires go into a 5 pin connector for the MB. The wires enter the connector at 2 of the side pins and the is a loop of wire coming out of the 1st & 3rd pins on the same end the the 2 wires enter. If this is a heat sensor, I don't see a place on the MB to plug it in anyway. I assume the heatsink is made to dissipate the heat anyway. Does anyone know for sure what the wires are for? Here is a pick of the CPU/heatsink with the 5 pin connector resting on top to the heatsink. Thanks, Terry

[Beta Geek]

I'd have to stick to thermistor theory. The reason you don't have any connector on your mobo for it is because the plug is most likely of proprietary design, which means it will only work with a mobo that was made by the same company that put the sensor in the heatsink. Acer, HP, Compaq, and many other manufactures never cease to amaze me when I have to work on their older models. Some of the newer ones aren't much better!

Beta Geek

[Reid]

Some heat sinks are grounded for shielding, but cannot be sure with your description of the connections.

"With microprocessor clock speeds rising above 1 GHz, the CPU's heatsink comes under increasing scrutiny as a source of electromagnetic interference (EMI)"

http://www.elecdesign.com/Articles/Index.cfm?ArticleID=3801

[saphalline]

Wow. I never thought about that before, Reid, but it makes sense. The physical design of a heatsink is perfect for capturing resonance signals! I wonder if adding some "force-feedback" to the CPU fan would nullify some of those unwanted RF waves? :p

[Reid]

I had seen a ground wire on a video card heatsink, so I did a Google search to see if it is also done on some CPU heatsinks. Never actually saw one.