2 Replies Latest reply on Feb 17, 2012 11:17 AM by

    Warning:  BXSTS100C Xeon CPU Cooler Users


      I set up a S5520SCR + SC5650WS + 2x E5620 setup using the Intel BXSTS100C CPU coolers.


      One of the CPU's ran pretty warm, sometimes up to 20°C hotter than the other. 


      Well, I had to RMA the motherboard and found out something interesting when I tore it down.  The heatsink baseplate is warped with a positive protrusion upwards from the copper CPU contact plate.  In other words, it's a negative clearance plane.  If anything (like the CPU socket) is not negative enough, it will cause the copper pad not to contact the CPU.  And it does just that on the S5520SCR socket.  One size of the steel baseplate protrudes over 0.033" up from the copper.  It's "brother" has positive clearance, it will not contact anything unless it's higher than the CPU top.


      This caused the defective the cooler to only hit on one edge of the CPU, while the good cooler contact all across the top the CPU.

        • 1. Re: Warning:  BXSTS100C Xeon CPU Cooler Users

          DOH!  Here's a pic of the tops of the CPU's, it shows the witness marks.  One CPU contacts all the way across, but the the other only contacts on one edge.  That TIM might "look" thick, but it's not.  I use about a 2mm ball of TIM in the center of the heatsink, then spread it out evenly in radial fashion to get 100% coverage.


          Something else to note, this design relies on the backing plate to be flat to get the right preload on the heatsink/CPU contact patch.  If the backing plate is warped, the loading is not correct, even if there is no physical contact between the backing plate and CPU socket.


          If anyone from Intel reads this, forward this to the QA or Eng'g dept.  I'll gladly ship one or both samples in exchange for units with positive clearance.  If I RMA to NewEgg, you might not ever see it.

          • 2. Re: Warning:  BXSTS100C Xeon CPU Cooler Users



            I have got a question regarding the bottom plate of the cpu cooler. Is it removable

            meaning can you detach the bottom plate from the square mid section which is copper.

            The reason behind is because I want to use this cooler for my 1155 xeon cpu and I quite like the estactic look of this cpu cooler.

            Hopefully by modding it.


            I would be very gratefull if you would answer my question.