M90S-6S vs APC Symmetra LX SYA16K16RMP
The Xtreme Power M90S-6S (with M90S-RMK rack-mount kit) and the APC Symmetra LX SYA16K16RMP are modular online double-conversion UPS for single-phase rack-mounted loads. The M90S-6S is an active, current-generation platform delivering significantly higher usable power, broader scalability, and assured long-term support, while the Symmetra LX is a discontinued legacy system.
Why the M90S-6S replaces the Symmetra LX
- About 40% more usable power — 18 kW (unity PF) vs 12.8 kW (0.8 PF).
- Scales 6–24 kVA in 6 kVA increments vs 4–16 kVA — higher maximum capacity.
- Up to 98% ECO / 93% online efficiency vs about 88.7% — lower operating and cooling cost.
- Universal module slots and a longer 3-year warranty on an active platform.
18 kVA modular UPS, side by side
| Specification | Xtreme Power M90S-6S | APC Symmetra LX SYA16K16RMP | Advantage |
|---|---|---|---|
| Product status | Active production | Discontinued (Aug 26, 2025) | Long-term platform availability |
| Capacity | 18 kVA / 18 kW (unity PF) | 16 kVA / 12.8 kW (0.8 PF) | About 40% more usable power |
| Topology | Online double-conversion | Online double-conversion | Equivalent protection |
| Modularity / scalability | 6–24 kVA in 6 kVA increments (up to 18 kVA N+1) | 4–16 kVA N+1 in 4 kVA increments | Higher maximum capacity |
| Rack space | 26U (45.5 in) | 19U (32.9 in) | APC is more compact at 19U; the M90S-6S delivers more total usable kW (18 vs 12.8) |
| Efficiency | Up to 98% ECO / 93% online | About 88.7% online | Lower operating cost and heat |
| Internal runtime | Up to 9 min @ 18 kW | Up to 6 min @ 12.8 kW | Longer internal runtime |
| Maintenance bypass | Standard | Standard | Equivalent serviceability |
| Module slot flexibility | Universal slots (power or battery) | Dedicated power & battery slots | Simpler expansion and sparing |
| Warranty | 3-year repair or replace | 2-year repair or replace | Longer standard warranty |
Capacity figures show usable watts: the M90S delivers unity power factor (kVA = kW), while the Symmetra LX is rated 0.8 PF, so its kVA rating overstates usable watts. The Symmetra LX is a discontinued platform; efficiency and runtime figures reflect typical configurations from manufacturer documentation.
Choosing between them
Both are modular online double-conversion UPS for single-phase rack loads, so the decision is mainly between an active, expandable platform and continuing a legacy install. Choose the M90S for full usable kW, higher efficiency, universal module slots, and assured factory support; the Symmetra LX generally only makes sense where an existing deployment is being maintained short-term.
Choose the M90S-6S if you need
- An active, long-term supported modular UPS platform
- Significantly higher usable power in the 18 kVA class
- Greater efficiency to reduce operating and cooling costs
- Simpler expansion and sparing with universal module slots
- Unity power factor output with no stranded kVA
- Longer standard warranty coverage
The Symmetra LX SYA16K16RMP may fit if you need
- Temporary continuation of an existing legacy deployment
- No requirement for future expansion or factory support
Related comparisons
Replacing a Symmetra LX or planning modular UPS?
Xtreme Power supports modular UPS sizing, N+1 redundancy planning, and smooth migration from legacy Symmetra LX systems across enterprise, healthcare, industrial, and public-sector infrastructure.