Convex and Concave Heat Spreaders
To make matters worse, heat spreaders are not merely rough, but due to the way they're manufactured, they aren't level, either. The following diagram exaggerates the problem for the purpose of illustration:
AMD’s heat spreaders are slightly higher in the center and Intel’s have higher edges. From my perspective, AMD's approach is better-suited for cooling. Due to the mounting pressure of the CPU cooler, the thermal compound is thinnest where most of the heat needs to be transferred. Thus, Intel CPUs deserve perhaps a touch more thermal paste, and you should take care that no air gaps form in the center.
How Thermal Paste Spreads under Pressure
The following animation illustrates how thermal paste escapes to the sides when pressure is applied. Later, we’ll discuss the relationship between a paste’s fluidity (how "liquid" it is, the opposite of viscosity) and the maximum mounting pressure in detail. For now, let’s just say that a paste with low viscosity is more suitable for low-pressure mounting methods, like Intel’s push pin method, than a "hard" paste.
The technical specifications of a thermal paste’s thermal resistance do not necessarily predict its real-world performance for a specific combination of CPU, paste, and cooler. A good heat sink can be crippled by a mismatched thermal compound. A good match between cooler and paste can achieve more than just blindly choosing an expensive thermal compound.
- Everything You Wanted To Know About Cooling A CPU
- Interaction Of The Heat Spreader And Heat Sink
- The Differences Between AMD And Intel Heat Spreaders
- Choosing The Right Paste: More Than A Matter Of Price
- Applying Thermal Paste, Part One
- Applying Thermal Paste, Part Two
- Why Do We Test Each Paste In Four Scenarios?
- Get Ready For The Thermal Compound Benchmarks!