Three names, one philosophy: the highest edge retention available in a production folder — at a price in skill and effort.
M390 is made by Böhler (Austria). CPM-20CV is made by Crucible (USA). ELMAX is made by Uddeholms (Sweden). They are not identical steels, but they are close enough in composition and performance that the knife community groups them together — and for practical EDC purposes, the grouping is justified.
All three are third-generation powder metallurgy steels with very high chromium (~20%) and vanadium content (~4%), heat-treated to 60–62 HRC in most production knives. The high chromium gives excellent corrosion resistance. The high vanadium carbide content gives outstanding edge retention — among the best available in any stainless steel. ELMAX has a slightly finer carbide structure than M390/20CV, which some sharpeners prefer, but the real-world cutting performance difference is minor.
M390 vs. 20CV: Is there actually a difference?
Composition is nearly identical. In independent CATRA and toughness testing, performance is within statistical noise. The practical difference is sourcing: American knife makers often spec 20CV (domestic supply), European makers use M390. Benchmade has used both. In your pocket, you will not be able to tell the difference. This is not a debate worth having.
What it's actually like to carry
M390/20CV at 61 HRC will hold a working edge longer than S35VN in almost any cutting task. The gap is meaningful — not a marginal few-percent improvement but a genuinely noticeable difference in how long between maintenance sessions. For a knife used primarily for food prep and box cutting (the majority of EDC use), M390 can go months between sharpenings under light use.
The cost is sharpening difficulty. The same high-vanadium carbide structure that resists deformation during cutting also resists abrasion during sharpening. Budget sharpening systems (pull-through carbide sharpeners, cheap whetstones) will struggle. To get the most from M390, you need diamond stones, quality ceramic rods, or a guided system like the Edge Pro. Sharpening on a leather strop maintains an edge that's already sharp but won't reprofile a dull blade. This is not a beginner's steel.
Toughness is the tradeoff. Higher hardness means more brittleness at the micro-scale. M390 knives are more prone to edge chipping from lateral stress — twisting in a cut, prying, hard impact — than S35VN or MagnaCut at comparable HRC. For pure slicing and EDC tasks this is irrelevant. For abuse use, it matters.
ELMAX specifically
ELMAX has a slightly different carbide structure — more uniform, smaller carbides — which gives it better "grindability" (easier to machine during knife production) and a slightly more refined sharpened edge. Some sharpeners find it takes a keener apex than M390. It appears in a smaller number of production knives but is well-regarded by premium makers like Benchmade (seasonal runs) and some custom makers.
M390 / 20CV / ELMAX vs. Adjacent Steels
◆ CarryIndex Verdict
M390/20CV is the right call when: edge retention is your primary metric, you have the sharpening skills and equipment to maintain it properly, and your use profile is predominantly slicing tasks (food, packages, cardboard) rather than abuse use. It rewards expertise and punishes neglect more harshly than S35VN.
MagnaCut is now the better all-rounder for most use cases — it matches or exceeds M390 on edge retention, offers dramatically better toughness, and has corrosion resistance that's genuinely superior. If you're buying new today, MagnaCut is the more intelligent choice unless you have a specific reason to want M390 (a particular knife model, established sharpening workflow, or collector preference).
Who should buy M390: serious EDC users with a quality diamond sharpening setup, collectors who value the pedigree of Böhler's Austrian mill, and anyone who finds themselves resharpening more often than they'd like on their current steel.
