Introduction
If you already know that 14C28N and Nitro-V are solid budget performers, you're ready for the big leagues. Premium powder metallurgy steels like M390, S90V, Elmax, and CPM-20CV occupy the top tier of EDC knife blade materials — offering extreme edge retention, exceptional corrosion resistance, and the ability to take a very fine edge. But with prices ranging from $120 to over $400, choosing between them requires understanding real-world trade-offs, not just spec sheet numbers.
This comparison breaks down how M390, S90V, Elmax, and CPM-20CV perform across the metrics that matter: edge retention, toughness, corrosion resistance, sharpenability, and value. We'll ground every claim in production knives you can actually buy from Kizer, WE Knife, and ArtisanCutlery.
For a budget-oriented companion piece, see our budget steel comparison guide covering the sub-$60 tier.
What Makes These Steels Premium?
All four steels are powder metallurgy (PM) products. Unlike conventional ingot steels, PM manufacturing atomizes molten steel into fine powder, then sinters it under heat and pressure. The result is a much finer and more uniform carbide structure — which translates directly into better edge retention and toughness at high hardness.
| Property | M390 (Böhler) | CPM-20CV (Crucible) | S90V (Crucible) | Elmax (Uddeholm) |
|---|---|---|---|---|
| Edge Retention | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ |
| Corrosion Resistance | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ |
| Toughness | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐ | ⭐⭐⭐⭐ |
| Sharpenability | ⭐⭐ | ⭐⭐ | ⭐⭐ | ⭐⭐⭐ |
Data reference: Steel compositions and properties are sourced from Knife Steel Nerds, powder metallurgy processing overview on Wikipedia, and manufacturer data sheets.
M390 — The All-Rounder Gold Standard
Böhler M390 is arguably the most famous premium EDC steel. Its composition of approximately 20% chromium, 4% vanadium, and 1.9% molybdenum gives it an extraordinary balance of edge retention and stainlessness.
Why choose M390:
- Exceptional edge retention — outlasts S35VN by 2-3x in CATRA testing
- Near-perfect corrosion resistance — essentially stainless in all but extreme saltwater
- Takes a very fine, aggressive edge
The trade-off: M390 is notoriously difficult to sharpen. Diamond abrasives are practically required, and reprofiling can be time-consuming.
Representative knives:
- The Kizer Drop Bear Zero M390 ($199.95) pairs M390 with Kizer's Button Liner Lock in a titanium/DLC build on its product page.
- The WE Knife Fluxor M390 ($343) is a titanium-handled flipper with nested liner lock — see it here.
- The ArtisanCutlery Tomahawk M390 ($224.99) offers M390 in a titanium handle package — product details.
CPM-20CV — M390's American Cousin
CPM-20CV is Crucible Industries' version of M390. The compositions are nearly identical (both hover around 20% Cr, 4% V, 1% Mo), and in blind testing most users cannot tell them apart.
Why choose 20CV:
- Identical performance to M390 at potentially lower cost
- Excellent for users who prioritize maximum edge holding over ease of sharpening
- American-made alternative
Where to find it: The Kizer Drop Bear Clutch Lock 20CV Fatcarbon ($198) is an excellent entry point — product page.
CPM-S90V — Maximum Abrasion Resistance
S90V takes edge retention to another level by packing approximately 9% vanadium into the alloy — more than double the vanadium content of M390/20CV.
Why choose S90V:
- The highest edge retention of any mainstream stainless steel
- Outlasts M390 by roughly 20-30% in abrasive cutting tests
- Excellent corrosion resistance (though slightly less than M390)
The trade-off: S90V is even more challenging to sharpen than M390. Its toughness is also the lowest of this group.
Representative knives:
- The ArtisanCutlery Fragarach S90V ($199.99) combines a titanium handle with S90V — see it here.
- The ArtisanCutlery Wizard S90V Copper ($139.99) offers S90V with a copper handle — product page.
Elmax — The Tough Performer
Uddeholm Elmax prioritizes toughness over raw edge retention. With its fine and evenly distributed carbide structure, it offers superior impact resistance.
Why choose Elmax:
- Best toughness of any premium PM stainless steel
- Still offers very good edge retention (close to S35VN)
- Easier to sharpen than M390 or S90V
- Good corrosion resistance
Representative knives:
- The Kizer Drop Bear Zero Elmax ($189.95) pairs Elmax with crystallized titanium — product page.
- The Kizer Drop Bear Clutch Lock Elmax Fatcarbon ($219) gives you Elmax in a crossbar-style lock platform.
Head-to-Head Comparison
Edge Retention
S90V > M390 ≈ 20CV > Elmax
In standardized CATRA tests, S90V outperforms M390 by about 25% in edge retention. M390 and 20CV are essentially tied. Elmax trails by roughly 30%, but still outperforms S35VN by a comfortable margin.
Toughness
Elmax > M390 ≈ 20CV > S90V
Elmax is in a different league for toughness. S90V demands respect — run a slightly more obtuse edge angle (17-20°) to compensate.
Corrosion Resistance
M390 ≈ 20CV > S90V > Elmax
M390 and 20CV are effectively stainless in any EDC context. S90V is close behind. Elmax can develop surface stains if neglected in very humid environments.
Sharpenability
Elmax > M390 ≈ 20CV > S90V
Elmax responds reasonably well to conventional alumina stones. M390 and 20CV need diamond or CBN. S90V demands diamond abrasives and patience.
Which Should You Buy?
Choose M390 or 20CV if you want the best all-around premium steel — excellent edge retention, total stainlessness, and a proven track record.
Choose S90V if edge retention is your absolute priority and you're willing to invest in diamond sharpening equipment.
Choose Elmax if you want premium corrosion resistance with better toughness and easier sharpening. It's the most forgiving premium steel for daily carry.
For the full Kizer lineup, check our Kizer knife buying guide. For WE Knife's premium offerings, see our best WE Knife titanium folders guide.
Conclusion
There's no wrong answer among these four steels — they all outperform budget options by a wide margin. Your choice comes down to your priorities: maximum edge holding (S90V), best all-round balance (M390/20CV), or superior toughness with easier maintenance (Elmax).
For those on a tighter budget wondering if the upgrade is worth it, our EDC knife sweet spot guide covers the $70-100 range where premium-adjacent steels like S35VN offer much of the performance at half the price.