Thermal Paste vs Liquid Metal vs PTM7950 Pads: Which Is Best for Your Device?

If you’ve ever wondered why your laptop runs hot even after a “cleaning,” the answer often lies in something most people never think about: the thermal interface material (TIM) sitting between your CPU or GPU and its heatsink.

Thermal paste, liquid metal, and PTM7950 phase-change pads are the three main contenders — and they are not interchangeable. Each has its place, its strengths, and its risks. Here’s what you actually need to know.

What Is a Thermal Interface Material (TIM)?

A TIM fills the microscopic air gaps between a processor’s heat spreader (or bare die) and the heatsink. Air is a terrible conductor of heat — so even a razor-thin layer of it can send temperatures soaring. The TIM’s job is to replace that air with something that conducts heat efficiently.

The better the TIM, the more efficiently heat moves from your chip to the heatsink — and ultimately out of your device.

Thermal Paste: The Trusted Workhorse

What it is: A compound made from silicone oil or other carrier fluids blended with thermally conductive fillers like zinc oxide, aluminium oxide, or silver particles. Premium options like Thermal Grizzly Kryonaut and Noctua NT-H2 sit at the top of the performance range.

Thermal conductivity: Typically 4–14 W/m·K depending on formulation.

Best For

• Desktop CPUs and GPUs
• Laptops during routine servicing
• DIY builds and home enthusiasts
• Situations where re-application every 2–5 years is acceptable

Pros

• Widely available and affordable
• Easy to apply — safe around components
• Electrically non-conductive (most variants)
• Repairable if you make a mess
• Works on virtually every processor type

Cons

• Degrades over time — eventually dries out and cracks
• Lower thermal conductivity ceiling vs liquid metal
• Requires periodic reapplication (every 2–5 years in laptops)

Liquid Metal: Maximum Performance, Maximum Risk

What it is: A gallium-based alloy — typically a blend of gallium, indium, and tin — that remains liquid at room temperature. The most well-known brand is Thermal Grizzly Conductonaut.

Thermal conductivity: 70–80 W/m·K — roughly 10× higher than premium thermal paste.

Best For

• High-performance gaming laptops (certain models)
• Enthusiast desktops where every degree counts
• Devices with bare-die CPU configurations
• Professional technicians with proper tools and experience

Pros

• Exceptional thermal conductivity — can drop temps by 10–30°C vs old paste
• Doesn’t dry out or degrade over time in the same way paste does
• Ideal for premium, high-TDP systems that are thermally constrained

Cons

• Electrically conductive — a spill can cause immediate, irreversible motherboard damage
• Reacts with aluminium — only safe on copper or nickel-plated heatsinks
• Extremely difficult to apply cleanly; requires masking components
• Migration risk over time — can flow to areas it shouldn’t
• Not suitable for beginners or DIY without proper experience

PTM7950 Phase-Change Pads: The Best of Both Worlds?

What it is: PTM7950 is a phase-change thermal interface material developed by Honeywell. It ships as a solid pad at room temperature, then transitions to a viscous, paste-like state once it reaches around 45–52°C during operation — at which point it conforms tightly to the surface.

Thermal conductivity: ~10–13 W/m·K (solid state spec), but real-world performance often rivals or exceeds high-end pastes due to superior surface conformance.

Best For

• Laptops where repasting is frequent or difficult
• Devices with uneven heatsink contact
• Repairs where long-term reliability matters
• Technicians who want a clean, mess-free application

Pros

• Extremely clean — simply cut to size and place; no spreading required
• Electrically non-conductive — safe around components
• Phase-change behaviour self-optimises under heat, filling gaps better than static paste
• Excellent long-term stability — does not dry out, crack, or pump out
• Performance on par with or better than mid-to-high-end thermal pastes
• Re-usable if opened carefully — lifts off cleanly

Cons

• More expensive than standard thermal paste
• Slightly lower peak conductivity ceiling vs liquid metal
• Requires the chip to reach operating temperature before optimal performance kicks in
• Less widely available than traditional paste

Side-by-Side Comparison

What Does BreakFixNow Use?

At BreakFixNow, our technicians assess each device individually before choosing the right thermal interface material. For most laptop repastes, we use high-quality thermal compound or PTM7950 pads depending on the device’s design and thermal requirements. For select high-performance gaming laptops where thermals are severely constrained, we offer liquid metal repaste as a premium service — applied with full component masking and proper technique.

We don’t cut corners on TIM quality, because a poor repaste is often worse than no repaste at all.

So, Which Should You Choose?

• Getting your everyday laptop serviced? Quality thermal paste or PTM7950 will serve you very well.
• Running a high-end gaming laptop that throttles under load? Ask about liquid metal — but only from a technician who knows what they’re doing.
• DIY on your own desktop or laptop? Thermal paste is the safest starting point. PTM7950 pads are worth the upgrade for a cleaner job.

If your device is running hotter than it should, a thermal repaste is often one of the best-value repairs you can do. It can restore years of performance in under an hour.

Frequently Asked Questions