Memory Foam vs High-Density Foam for Pressure Relief: What Is the Difference
Quick answer: the two terms are often confused because they overlap, but they measure different things. Density (kg/m3) is how much material is packed into the foam, it determines durability and how well the foam resists sagging. Memory foam describes a behaviour, a viscoelastic foam that slowly moulds to the body and slowly recovers its shape, rather than pushing back immediately like standard foam. Memory foam is usually made at a higher density, which is why the two get used almost interchangeably, but a foam can be high-density without being memory foam, and technically low-density memory foam exists too, though we don't sell it.
What "high density" actually measures
Density is a manufacturing measurement: kilograms of foam material per cubic metre. It tells you nothing about how the foam feels on first touch, a high-density foam can be manufactured firm or soft. What it does tell you is durability: higher-density foam resists permanently compressing under repeated, sustained weight far better than low-density foam, which is why a published density number is a genuine quality signal and a firmness label alone is not.
What "memory foam" actually measures
Memory foam, more precisely viscoelastic foam, is defined by how it responds to pressure and temperature: it softens slightly under body heat and pressure, slowly moulds around the shape pressing into it, then slowly recovers once the pressure is removed. That slow, contouring response is what spreads body weight over a wider surface area instead of pushing back evenly everywhere, which is the specific mechanism that reduces concentrated pressure at the hips and shoulders.
Why the two terms get confused
In practice, most genuine memory foam products are also high-density, because a low-density memory foam breaks down quickly and stops behaving like memory foam within months. So "high-density foam" and "memory foam" describe the same physical products often enough that people use them as synonyms. They aren't synonyms: density is about durability and structure, memory foam is about the specific slow-contouring feel. Our Ultra 200 and Revive are both high-density AND memory foam. Our Active Foam is high-density-adjacent (50 kg/m3) but is a more responsive, non-memory foam, it pushes back faster and contours less.
Pressure relief mechanism, compared directly
| Standard responsive foam (e.g. Active Foam) | Memory foam (e.g. Revive, Ultra 200) | |
|---|---|---|
| Response to pressure | Pushes back quickly, less moulding | Slowly moulds around the body shape |
| Pressure distribution | More even but less contouring at specific joints | Concentrates less pressure at hips and shoulders specifically |
| Motion transfer | Moderate | Low to zero |
| Feel | Firmer, more responsive | Softer surface feel, firmer support underneath |
| Density in our range | 50 kg/m3 | 65 kg/m3 (Revive) / 60-density layers, 65-density core (Ultra 200) |
When memory foam's contouring specifically helps
If your discomfort is localised, a specific hip, shoulder or knee that's tender to pressure, memory foam's slow-contouring behaviour is generally the more relevant construction, because it spreads load away from that specific point rather than pressing evenly (and therefore still firmly) against it. If your priority is a firmer, more responsive surface at a lower price and pressure at specific joints isn't the main issue, a standard high-density foam like our Active Foam is a legitimate, honest option, it's simply built for a different priority.
Talk to your healthcare provider first
This article explains foam terminology and construction, not medical treatment. Your doctor, rheumatologist or physiotherapist is the right person to advise on what suits your specific joints and condition.
Frequently asked questions
Is memory foam the same as high-density foam?
Not exactly. Density (kg/m3) measures how much material is in the foam and affects durability. Memory foam describes a slow-contouring behaviour. Most genuine memory foam is also high-density, but the two terms measure different properties.
Which is better for joint pain, memory foam or standard high-density foam?
For pressure concentrated at a specific joint, memory foam's slow-contouring behaviour generally spreads pressure more effectively. For overall firmness at a lower cost with less joint-specific contouring, a standard high-density foam is a legitimate alternative.
What density is Mr Mattress's memory foam?
Revive uses a 65 kg/m3 SABS-approved core. Ultra 200 uses 60-density, SABS-certified open-cell memory foam comfort layers over a 65-density Chip foam foundation core.
Does a higher density always mean a firmer mattress?
No. Density and firmness are different properties. A foam can be manufactured at a high density and still feel soft on the surface, density primarily affects durability and support, not surface feel.
Can memory foam cure or relieve arthritis?
No. Memory foam is a construction and comfort feature. It does not treat, relieve or cure arthritis, joint pain or any medical condition. Speak to your doctor or rheumatologist about your condition.
Related guides: Best mattress for rheumatoid arthritis in South Africa · Firm or soft mattress for arthritis · Best mattress for joint and hip pain · Full range spec comparison
Reviewed by Andries Taljaard, Founder of Mr Mattress. This article is general information about mattress construction, not medical advice.