Thermal Grizzly's PhaseSheet PTM Pro Cools Better at a Price

Thermal Grizzly has launched the PhaseSheet PTM Pro, a phase-change thermal pad that recorded a temperature difference of 5.83°C under a 240W heat load — the lowest among all materials the company tested, ahead of its own KryoSheet at 6.13°C and the original PhaseSheet PTM at 6.36°C. The new sheet sells for $23.28 in a 40 x 40mm size, a sharp premium over the original, which costs $13.92 for a larger 50 x 40mm sheet.

What changed in the Pro version?

The company promises two improvements over the original: higher thermal conductivity and a redesigned carrier film. The film peels away more easily from both sides, which reduces the risk of tearing the sheet during installation. That may read as a minor change, but anyone who has fought a fragile pad while fitting a heatsink knows the difference it makes.

The underlying material works the same way as before. At room temperature the sheet stays solid, like a conventional thermal pad. Above 45°C it turns into a very low-viscosity liquid that behaves much like thermal paste.

The takeaway: same phase-change mechanism as the original, but better heat transfer and a sheet that is harder to damage during fitting.

Why phase-change material matters

The liquid state addresses a known weakness of traditional paste: the pump-out effect. Pump-out happens when paste gradually moves out from between a heatsink and a GPU die or CPU integrated heat spreader. Repeated thermal expansion and contraction of the contacting surfaces drives this migration. Over time, less paste covers the contact area, and cooling performance can degrade.

A material that turns liquid only when hot, and re-solidifies when cool, keeps filling the gap through many thermal cycles. In plain words, the pad stays where the paste would slowly disappear.

How did it perform in testing?

Thermal Grizzly shared a performance graph from controlled testing. The test setup used:

• a 30 x 30mm contact area
• 300N of mounting force, equal to 48 PSI
• a 240W heat load

Under those conditions the PhaseSheet PTM Pro recorded the 5.83°C temperature difference. The full ranking:

• PhaseSheet PTM Pro: 5.83°C
• KryoSheet: 6.13°C
• Duronaut Pro: 6.29°C
• PhaseSheet PTM (original): 6.36°C

These are the manufacturer's own figures rather than independent measurements, so treat them as a company benchmark until third-party reviews confirm them.

Where can you use it?

The pad is reusable and electrically non-conductive. That makes it safe on components without an integrated heat spreader, including mobile CPUs and GPUs. It also suits internal components such as memory and storage.

The takeaway: one sheet can cover bare dies that would risk a short circuit with conductive interface materials.

Is the price justified?

At $23.28 per 40 x 40mm sheet, the Pro costs roughly 67 percent more than the original PhaseSheet PTM while covering 20 percent less area. Buyers pay that premium for a 0.53°C improvement over the original pad in the company's own test — a margin that matters most in high-heat-density builds, such as high-end GPUs or compact systems with tight thermal budgets.

For a single-sheet repair or a flagship graphics card repaste, the price is defensible. For budget builds, the original PTM remains the better value per square millimeter.

The PhaseSheet PTM Pro is available now through Thermal Grizzly's website, and its success will depend on whether independent testing confirms the company's numbers against the pastes it claims to beat.