Thermal Putty vs. Thermal Pads
Both fill the gap between components and heatsinks. Pads win when the gap is uniform and measurable. Putty wins when the geometry is complex or the height varies between adjacent chips.
The deciding factor: if all the chips you are cooling are the same height and the gap is consistent, use pads. If the heights vary between adjacent components or the shape is irregular, use putty.
For uniform, measurable gaps
Thermal Pads
- +Pre-cut to exact thickness (0.5 / 1.0 / 1.5 / 2.0mm)
- +Consistent performance, same result every time
- +Clean, precise coverage on flat rectangular chips
- +Best choice for VRAM, VRM, M.2 SSDs
- −Must measure gap beforehand; wrong thickness means poor contact
- −Poor fit for components at different heights
For complex or mixed-height layouts
Thermal Putty
- +Hand-moldable; fills any shape without pre-measuring
- +Bridges height differences between adjacent components
- +Reusable indefinitely if not contaminated
- +Ideal for DIY electronics and custom cooling
- −Less precise than pads on flat, uniform surfaces
- −More effort to apply neatly in tight spaces
When pads are the better choice
Thermal pads excel wherever the gap between a chip and its heatsink plate is consistent and measurable. VRAM chips on a GPU sit at a known height; the gap between the chip surface and the backplate or heatsink plate can be measured from the original pad thickness. You cut a pad to match the footprint of each chip, press it in place, and reassemble.
The same applies to M.2 SSDs, where the gap between the SSD surface and the heatsink is defined by the drive spec or heatsink foam thickness. Pads are the standard solution here because the geometry is simple, flat, and rectangular.
Do not stack multiple pads to reach a thickness not available in a single piece. This creates an internal interface between the two pads and degrades thermal performance. Use a single pad of the correct thickness, or switch to putty if the right thickness is unavailable.
When putty is the better choice
Thermal putty becomes the right tool when the geometry stops being flat and uniform. The most common scenario is a custom cooling project with mixed-height components: LED driver boards where capacitors and inductors sit at different heights, power delivery modules with inductors that protrude higher than surrounding chips, or custom PCBs where several adjacent components all sit at slightly different heights.
Covering each component individually with a correctly-sized pad is technically possible but requires measuring each height, ordering multiple pad thicknesses, and cutting around irregular shapes. Putty lets you apply one continuous piece that conforms to the entire surface, filling every gap regardless of height variation.
For GPU VRM components specifically, putty is an alternative when the VRM layout is irregular or components sit at varying heights. Pads are still the cleaner choice for regular flat VRM chips.
Reusability
Thermal pads can be reused 2–3 times if handled carefully. Remove them cleanly, avoid stretching, and store flat. Putty can be reused indefinitely as long as it is not contaminated with dust or debris. If it picks up particles from the PCB during removal, discard that portion and use fresh material.