Arctic MX-4

In direct comparative testing, MX-4 measured a modest but real 1.5°C behind the top-performing compound tested, a gap that's genuinely negligible for mainstream CPUs like a Core i5 or Ryzen 5 that don't generate enough sustained heat to make that difference meaningful in practice. Current guides specifically recommend MX-4 for exactly this CPU tier, noting these chips don't need premium paste to achieve excellent results.

As a carbon-based, non-metallic compound, MX-4 shares the same fundamental safety profile as its MX-6 successor: fully non-conductive, safe for less experienced builders, and free of the short-circuit risk that comes with metal-based or liquid-metal alternatives.

MX-4's application profile is well-documented across a decade of widespread use, with an extensive body of user experience confirming consistent, predictable spreading behavior under cooler mounting pressure, a genuine advantage of a product with this much real-world track record behind it.

Fully non-conductive composition means MX-4 carries no risk of shorting components even with an imperfect application, the same safety profile that's made the broader Arctic MX line a standard recommendation for cautious or first-time builders for years.

While MX-6 specifically improved on pump-out resistance over this MX-4 formula, MX-4 still offers solid multi-year longevity appropriate for mainstream builds that aren't opened and repasted frequently, though buyers specifically prioritizing the longest possible interval between applications should consider stepping up to MX-6 instead.

Against the Arctic MX-6, covered elsewhere on this site, that paste delivers a measured 20% thermal resistance improvement and better pump-out resistance for only a small price increase, generally the smarter buy for anyone not on the absolute tightest budget. Against Thermal Grizzly Kryonaut, also covered elsewhere on this site, that premium paste outperforms MX-4 by a real but modest margin, a difference that matters more for high-TDP flagship CPUs than for the mainstream chips MX-4 is best suited to.

Mainstream CPU builds on the tightest thermal-paste budget. Current guides specifically recommend this tier of paste for chips like a Core i5 or Ryzen 5.

Buyers who value an extremely long, proven track record over the newest formula. Few thermal pastes have this much accumulated real-world usage data behind them.

Not for flagship or heavily overclocked CPUs. Arctic's own MX-6, or Thermal Grizzly Kryonaut, both covered elsewhere on this site, deliver meaningfully better performance where that headroom actually matters.

Not for buyers who want the longest possible interval between repasting. MX-6's improved pump-out resistance is the better choice for that specific priority.