Not all thermal pastes are created equal. The paste you choose for laptop repasting can mean the difference between a 10°C temperature drop and a 20°C improvement. This guide compares the top thermal pastes for laptops, tests their real-world performance, and shows you exactly what to buy based on your laptop type and budget.
| Paste | Thermal Conductivity | Price (UK) | Longevity | Best For |
|---|---|---|---|---|
| Arctic MX-6 | 4.0 W/mK | £5–7 | 4–6 years | Budget builders, office laptops |
| Thermal Grizzly Kryonaut | 6.0 W/mK | £12–18 | 3–5 years | Gaming & high-end gaming laptops |
| Noctua NT-H2 | 4.0 W/mK | £10–13 | 5–8 years | Workstations, longevity focus |
| Thermal Grizzly Conductonaut | 7.4 W/mK (liquid metal) | £20–25 | 2–3 years | Not recommended for most laptops |
| Sabrent Thermal Paste | 3.5 W/mK | £3–5 | 2–3 years | Temporary fixes, budget survival |
What Does Thermal Conductivity Mean?
Understanding W/mK (Watts per Meter Kelvin)
Thermal conductivity measures how quickly heat transfers through the paste from the CPU die to the heatsink. Higher numbers = faster heat transfer = cooler CPU. The scale runs roughly:
- 3.0–3.5 W/mK: Low-end pastes. Still functional but slower heat transfer, more temp gain after pump-out.
- 4.0 W/mK: Sweet spot for most applications. Arctic MX-6 and Noctua NT-H2 hit this point with great longevity.
- 5.0–6.0 W/mK: Premium performance. Kryonaut at 6.0 W/mK shows measurable benefit (1–3°C cooler) in real gaming scenarios.
- 7.0+ W/mK: Exotic options (liquid metal). Not worth the risk in compact laptop layouts.
Real-World vs. Marketing Numbers
A paste rated at 6.0 W/mK isn’t twice as cool as a 3.0 W/mK paste. In laptops, you might see:
- Arctic MX-6 (4.0) to Kryonaut (6.0): ~2–4°C improvement under full load.
- Arctic MX-6 to Conductonaut (7.4): ~3–5°C improvement, but with more risk.
The main bottleneck isn’t paste—it’s the contact surface and heatsink design. A £6 Arctic MX-6 with perfect contact beats a £20 Kryonaut with poor seating every time.
Top Pick: Arctic MX-6 — Best Value
Why Arctic MX-6 Dominates Budget Repasting
Arctic MX-6 is the most popular thermal paste for laptop repasting, and for good reason:
- Price: £5–7 per tube (often under £6 with multi-packs).
- Performance: 4.0 W/mK—excellent for the price.
- Non-conductive: Safe to apply in tight laptop spaces without risk of shorts.
- Longevity: 4–6 year lifespan, decent pump-out resistance.
- Availability: Stocked on Amazon UK, Overclockers, Scan.
Real-World Performance
Repasting with Arctic MX-6 typically drops laptop temperatures by 10–20°C compared to degraded factory paste. In our testing:
For step-by-step guidance, check out our complete thermal paste application guide and thermal paste replacement guide.
- Office/business laptops: 12–15°C improvement, dropping idle temps from 55°C to 40°C.
- Gaming laptops: 15–20°C improvement, dropping load temps from 95°C to 75–80°C.
- Combined with fan cleaning: Additional 5–10°C improvement for total 20–30°C gain.
Who Should Buy Arctic MX-6?
- First-time laptop repasters (safest choice—non-conductive).
- Office and business laptops (light thermal loads).
- Budget-conscious users.
- Anyone wanting a long-lasting, pump-out-resistant paste.
Drawbacks
- Not the highest thermal conductivity (6.0 W/mK options exist).
- Slightly longer curing time (24 hours for full performance) compared to Kryonaut (2–4 hours).
Bottom line: If you’re buying one paste for your laptop, buy Arctic MX-6. It’s the best all-rounder.
Premium Performance: Thermal Grizzly Kryonaut
When Maximum Cooling Matters
Thermal Grizzly Kryonaut is the go-to for enthusiasts and gaming laptops:
- Thermal conductivity: 6.0 W/mK (50% higher than Arctic MX-6).
- Price: £12–18 per tube.
- Curing time: 2–4 hours to full performance (faster than Arctic).
- Application: Slightly thicker consistency, doesn’t spread as easily as Arctic.
- Longevity: 3–5 years typical (slightly shorter pump-out window than Arctic).
Performance Gains vs. Arctic MX-6
In real-world testing on gaming laptops:
- Idle temperature: Negligible difference (both 30–40°C).
- Full load temperature: 2–4°C cooler with Kryonaut in sustained gaming.
- Throttling threshold: Kryonaut allows 5–10 extra minutes of gaming before thermal throttling kicks in.
Is 2–4°C worth the extra £7–11? For gaming laptops running at 85°C+, yes—that 2°C drop can prevent throttling and extend session length.
Who Should Buy Kryonaut?
- High-end gaming laptop owners (RTX 4080 and above).
- Content creators doing heavy rendering (sustained high thermal load).
- Competitive esports gamers needing maximum sustained performance.
- Users with naturally high-ambient-temperature rooms (25°C+).
Drawbacks
- Premium price (2–3x Arctic MX-6).
- Slightly shorter lifespan (3–5 years vs. 4–6 with Arctic).
- Overkill for office laptops or light gaming.
- Slightly thicker consistency makes application messier for beginners.
Value verdict: Good for gaming, overkill for business laptops.
Longevity Champion: Noctua NT-H2
The Workstation Choice
Noctua NT-H2 is engineered for ultra-long service life, particularly in sustained-load scenarios:
- Thermal conductivity: 4.0 W/mK (same as Arctic MX-6).
- Price: £10–13 per tube.
- Longevity: 5–8 years (industry-leading pump-out resistance).
- Consistency: Slightly thicker, easier to apply cleanly than Arctic.
- Bonus: Includes lens cleaning wipes (handy for fans).
Real-World Use: Workstations & Content Creators
Noctua NT-H2 shines in laptops used for long render sessions and 24/7 operation:
- Video editors doing all-day rendering runs.
- Machine learning engineers with sustained GPU loads.
- 3D artists running overnight renders.
In these scenarios, paste pump-out happens faster due to constant thermal cycling. Noctua’s superior longevity means your repasting stays effective 1–2 years longer than cheaper alternatives.
Who Should Buy Noctua NT-H2?
- Content creators expecting to keep their laptop 5+ years.
- Workstation laptop owners.
- Users who repaste infrequently (don’t want to open their laptop again for years).
- Anyone prioritizing longevity over raw thermal performance.
Drawbacks
- Premium price (2x Arctic MX-6).
- Thermal conductivity identical to Arctic (no performance edge).
- Overkill for casual users.
Value verdict: Excellent investment for workstations; unnecessary for casual gaming.
Avoid: Liquid Metal Pastes (Conductonaut, Hydronaut)
Why Liquid Metal Isn’t Right for Laptops
Liquid metal pastes like Thermal Grizzly Conductonaut (7.4 W/mK) achieve the highest thermal conductivity but are highly conductive electrically. In laptops:
- Component spacing: Laptop motherboards are densely packed. One accidental spill onto a capacitor or MOSFET shorts your board instantly.
- Vibration risk: Laptop movement can cause liquid metal to migrate away from the CPU, creating dry spots and reduced cooling.
- Thermal cycling: Liquid metal thickens and hardens in extreme cold, potentially cracking connections.
- Cost: £20–25 per tube, and professional service ($100+) is usually needed for application.
Real-World Temperature Gain
Even if you apply liquid metal successfully, the temperature improvement over Kryonaut is marginal:
- Kryonaut (6.0) to Conductonaut (7.4): 1–2°C improvement, not 5°C.
- Arctic MX-6 to Conductonaut: 3–5°C improvement, but with massive risk.
Verdict: Not worth it for laptops. Stick with Kryonaut for maximum safe thermal performance.
Budget Pastes: Sabrent, Kingpin, Thermal Paste from Unknown Brands
When £3–5 Pastes Make Sense
Ultra-cheap pastes (£3–5) exist but come with trade-offs:
- Thermal conductivity: Often 3.0–3.5 W/mK (lower than Arctic).
- Longevity: 2–3 years before pump-out becomes severe.
- Pump-out resistance: Tends to degrade faster than premium brands.
Are They Worth Using?
Rarely. The difference between a £3 paste and a £6 Arctic MX-6 isn’t huge, but it adds up:
- 2–3°C cooler with Arctic.
- 2 extra years of useful lifespan.
- Better brand support if issues arise.
For a few extra pounds, invest in Arctic MX-6. You’ll repaste less often and get better temperatures. Save the £3 pastes for emergency repair kits in a pinch.
Thermal Paste Comparison Cheat Sheet
| Paste Name | Thermal Conductivity | UK Price | Lifespan | Best Use | Risk Level |
|---|---|---|---|---|---|
| Arctic MX-6 | 4.0 W/mK | £5–7 | 4–6 years | General repasting | Very low |
| Thermal Grizzly Kryonaut | 6.0 W/mK | £12–18 | 3–5 years | Gaming laptops | Low |
| Noctua NT-H2 | 4.0 W/mK | £10–13 | 5–8 years | Workstations | Very low |
| Conductonaut (liquid metal) | 7.4 W/mK | £20–25 | 2–3 years | Desktops only | Very high |
| Sabrent / budget brands | 3.0–3.5 W/mK | £3–5 | 2–3 years | Emergency only | Low (but lower performance) |
How to Choose the Right Paste for Your Laptop
Decision Tree
Is your laptop a gaming machine? → Kryonaut (£12–18)
Is your laptop a workstation or do you render often? → Noctua NT-H2 (£10–13)
Is your laptop office/business class? → Arctic MX-6 (£5–7)
Is your budget extremely tight? → Arctic MX-6 (still the best value—don’t go lower)
Is your thermal load extreme (CUDA rendering 24/7)? → Kryonaut + cooling pad combo
Application Tips for Best Performance
Pea-Grain Application (Recommended for Laptops)
- Apply a pea-sized dot in the center of the CPU die.
- Let the heatsink pressure spread it—don’t pre-spread manually.
- Over-application reduces thermal contact (paste acts as insulation when thick).
Thermal Paste Curing Time
- Arctic MX-6: 24 hours to peak performance. You can use it immediately but expect slightly higher temps for the first day.
- Kryonaut: 2–4 hours to full performance. Noticeably faster.
- Noctua NT-H2: 12 hours recommended. Slightly slower than Kryonaut.
Surface Preparation
Before applying new paste:
- Clean the CPU die with isopropyl alcohol (90%+) and lint-free cloth.
- Clean the heatsink base plate as well—old paste residue interferes with new paste contact.
- Allow isopropyl to evaporate completely (5 minutes) before applying paste.
- Avoid touching the CPU die after cleaning—skin oils reduce contact.
Where to Buy Thermal Paste in the UK
- Amazon UK: Best selection, fast delivery, price-competitive. Check for multi-packs to save.
- Overclockers UK: Gaming-focused, good prices on Kryonaut and premium pastes.
- Scan.co.uk: Competitive pricing, especially for bulk purchases.
- CeX: Physical stores, good for emergency same-day purchases.
- Local PC shops: Often stock Arctic MX-6 in-store.
Tip: Buy a multi-pack if you’re repasting several devices. Arctic MX-6 often comes in 3-packs for £12–14, dropping per-tube cost to £4–5. Combined with proper fan cleaning and maintenance, quality paste delivers the best thermals.
Frequently Asked Questions
Is thermal paste conductive?
Most laptop thermal pastes are non-conductive, meaning they won’t short electronics if spilled. Arctic MX-6, Kryonaut, and NT-H2 are all non-conductive and safe for compact laptop layouts. Liquid metal pastes (Conductonaut) are highly conductive and should not be used in laptops.
How much thermal paste should I use?
Use a pea-grain amount—roughly the size of a pea (about 3mm diameter). This is about 0.1–0.2 grams. The heatsink pressure will spread it evenly across the die. More paste doesn’t mean better cooling; excess paste actually insulates and reduces thermal transfer.
Can I mix different pastes?
Avoid it. Different pastes have different curing times, particle sizes, and thermal properties. Mixing them can create inconsistent thermal contact. Always use one paste type and clean off old paste completely before applying new paste (even if it’s the same brand).
Should I repaste my GPU separately from my CPU?
Yes, many gaming laptops have separate CPU and GPU dies with independent thermal paste. Check your laptop’s service manual. If both are under one heatsink assembly, you can paste both at the same time. If they’re cooled separately, repaste both.
Does thermal paste expire?
Thermal paste doesn’t truly “expire,” but performance degrades if stored improperly. Unopened tubes last 3–5 years in cool, dry storage. Once opened, use within 1–2 years. Heat, humidity, and light exposure accelerate degradation.
Is it worth spending £18 on Kryonaut vs. £6 on Arctic?
For most gaming laptops, yes—you’ll see 2–4°C cooler load temperatures, which can prevent throttling. For office laptops, no—Arctic is overkill already and Kryonaut is wasted performance. Gaming laptops pushing 85°C+ benefit most from premium paste.
What’s the difference between Kryonaut and Kryonaut Extreme?
Thermal Grizzly released “Kryonaut Extreme” as an improved variant (6.5 W/mK, slightly longer lifespan). The difference is marginal (0.5°C) and costs the same or more. Standard Kryonaut is still excellent for laptops.
Can I use desktop thermal paste in my laptop?
Yes, as long as it’s non-conductive. Most desktop pastes (Arctic Silver, Coollaboratory, etc.) work fine in laptops. However, desktop pastes often assume larger CPU dies and might apply differently. Laptop-targeted pastes like Arctic MX-6 are formulated for smaller dies and tighter spaces.
