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Seasonic Vertex PX-1200 — 1200 W · 80+ Platinum · ATX 3.0
Seasonic

Seasonic Vertex PX-1200

1200 W · 80+ Platinum · ATX 3.0

93
/ 100
From $289
VS
Seasonic Vertex PX-1200 wins by 3
Corsair RM850x Shift — 850 W · Gold
Corsair

Corsair RM850x Shift

850 W · Gold

90
/ 100
From $179
Specdex verdict

Seasonic Vertex PX-1200 takes it — here’s why.

In our weighted Specdex score, Seasonic Vertex PX-1200 lands at 93 and Corsair RM850x Shift at 90. That puts Seasonic Vertex PX-1200 ahead by 3 points — a narrow margin driven mostly by its strengths in the categories below.

Pick Seasonic Vertex PX-1200 if…

  • ✓Rock-solid ripple
  • ✓Platinum efficiency
  • ✓Long 12-year warranty

Pick Corsair RM850x Shift if…

  • ✓Modular cabling on most
  • ✓ATX 3.1 / 12V-2x6 support
  • ✓10-year warranty on many
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Winner by scenario

Derived from the sub-score breakdown · not a separate test

Efficiency

Seasonic Vertex PX-1200

Compared on the efficiency sub-score

Seasonic Vertex PX-1200 leads on efficiency (96 vs 90).

Noise

Seasonic Vertex PX-1200

Compared on the noise sub-score

Seasonic Vertex PX-1200 leads on noise (92 vs 86).

Cables

Seasonic Vertex PX-1200

Compared on the cables sub-score

Seasonic Vertex PX-1200 leads on cables (90 vs 86).

Value for money

Corsair RM850x Shift

Specdex score per dollar at MSRP

Corsair RM850x Shift more score per dollar ($179 vs $289).

Seasonic Vertex PX-1200 93
vs
90 Corsair RM850x Shift

Score breakdown

Seasonic Vertex PX-1200
93
efficiency 96
noise 92
cables 90
value 86
Corsair RM850x Shift
90
efficiency 90
noise 86
cables 86
value 84

Specs side-by-side

Seasonic Vertex PX-1200 versus Corsair RM850x Shift — full spec comparison
Spec Seasonic Vertex PX-1200 Corsair RM850x Shift
Wattage
1200 W
850 W
Efficiency
80+ Platinum
Gold
Standard
ATX 3.0
—
Connectors
1× 16-pin 12VHPWR (600W)
—

Seasonic Vertex PX-1200

Pros
  • +Rock-solid ripple
  • +Platinum efficiency
  • +Long 12-year warranty
Cons
  • −Heavy at 2.6 kg
  • −Expensive
  • −Cables stiff

Corsair RM850x Shift

Pros
  • +Modular cabling on most
  • +ATX 3.1 / 12V-2x6 support
  • +10-year warranty on many
Cons
  • −Bulky on higher wattages
  • −Fan noise varies by load
  • −Cable length may not fit some cases

FAQ: Seasonic Vertex PX-1200 vs Corsair RM850x Shift

Which is better, Seasonic Vertex PX-1200 or Corsair RM850x Shift? +

Seasonic Vertex PX-1200 scores 93 on our weighted rubric — ahead by 3. Your best pick depends on the sub-scores above.

Is Seasonic Vertex PX-1200 worth the price? +

At $289, Seasonic Vertex PX-1200 delivers a Specdex score of 93 — strongest in efficiency.

Is Corsair RM850x Shift worth the price? +

At $179, Corsair RM850x Shift delivers a Specdex score of 90 — strongest in efficiency.

Does Seasonic Vertex PX-1200 or Corsair RM850x Shift last longer? +

Based on our long-term update and support ratings, both ship with multi-year support. Battery and reliability scores are visible in the breakdown above.

Which is better for efficiency, Seasonic Vertex PX-1200 or Corsair RM850x Shift? +

Seasonic Vertex PX-1200 — leads on efficiency (96 vs 90). Compared on the efficiency sub-score.

Which is better for noise, Seasonic Vertex PX-1200 or Corsair RM850x Shift? +

Seasonic Vertex PX-1200 — leads on noise (92 vs 86). Compared on the noise sub-score.