Table of Contents
Advertisement
AMD Athlon™ 64 and AMD Opteron™ Processors
Thermal Design Guide
The reference spring clip material is the heat-treatable spring steel, SK7. AMD strongly
recommends using SK7 or an equivalent material for the spring clip. The clip should be plated
after heat treatment for cosmetic and anti-corrosive reasons. Table 5 gives the chemical
composition of SK7. The heat treatment used should bring the ultimate strength of the material to
a minimum of 1,300 Mega-Pascals (Mpa) or 189 Kilo-pounds per square inch (Ksi) and a yield
strength to 940 MPa (or 136 Ksi).
Other materials commonly used for heatsink spring clips have been shown to yield under the high
load of the initial spring clip deflection, become deformed, and can no longer apply the same load.
Table 5. Chemical Composition of SK7 Spring Steel
Composition
C
0.60–0.70
Si
Maximum 0.35
Mn
0.80–0.90
P
Maximum 0.030
S
Maximum 0.030
Fe
Remaining Balance
2.6.3 Retention Frame
The retention frame serves multiple purposes. During installation, the retention frame provides a
stop for the spring clip ends used in the thermal reference design solution 1. The retention frame
also aligns the heatsink and provides a stop for the heatsink in case of a large shock-force event.
The retention frame serves to hold the solution 1 heatsink assembly together as a single unit for
shipping and assembly, and aligns and helps to retain the EMC shield.
The retention frame serves the same function for the thermal reference design solution 2, but it is
implemented in a different way. The retention frame and backplate are joined to the motherboard
by the motherboard manufacturers. Two screws securely hold the backplate and retention frame
together. The six mounting tabs on the retention frame serve as an attachment point for the
heatsink spring clip. The thermal reference design solution 2 utilizes only two of the mounting
tabs, but the flexibility of the design is increased with the additional mounting tabs.
2.6.4 Heatsink
The footprint of the reference design heatsink is 77x68 mm. The highest-power processors may
require solutions incorporating copper in the base of the heatsink to dissipate heat, taller fins and
greater fin density to increase surface area, and higher flow fans to increase cooling capacity.
Because the processor mounting surface extends above the surface of the cam box on the socket,
the heatsink bottom must be flat. The heatsink must have a flat surface of at least 40x40 mm
centered over the processor as specified in the reference design drawing.
26
AMD Athlon™ 64 and AMD Opteron™ Processors Thermal Requirements Chapter 2
Preliminary Information
Percentage of the Element
26633 Rev. 3.03 September 2003
Advertisement
Table of Contents
