$137.70
The APC BE850G2 and the CyberPower ST900U are evenly matched, rated 2.9 and 2.9. The CyberPower ST900U wins on features and value. The CyberPower ST900U costs $17.75 less ($119.95 vs $137.70).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
CyberPower ST900U
A standby UPS for a mid-range desktop PC when you do not need AVR or an LCD.
Amazon $119.95$119.95
Which should you buy?
- Choose the CyberPower ST900U for features (USB charging, software or network management vs USB charging) and value ($23.99 per 100 W ($119.95, 500 W) vs $30.60 per 100 W ($137.70, 450 W)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every desktop (under 1,000 VA) UPS battery backup; a clear win is highlighted. How we rank explains each one.
| Factor weight | APC BE850G2 | CyberPower ST900U |
|---|---|---|
| Overall rating | 2.9/5 | 2.9/5 |
| Value 25% | 66 $30.60 per 100 W ($137.70, 450 W) | 77 $23.99 per 100 W ($119.95, 500 W) |
| Output 15% | 13 450 W rated output | 16 500 W rated output |
| Topology and waveform 20% | 50 topology and waveform not published (neutral score used) | 0 standby, simulated sine wave |
| Runtime 10% | 38 35 min at 100 W | 50 runtime at 100 W not published (neutral score used) |
| Features 15% | 15 USB charging | 35 USB charging, software or network management |
| Warranty 15% | 40 3-year warranty, $75,000 equipment guarantee | 47 3-year warranty, $125,000 equipment guarantee |
Specifications
| APC BE850G2 | CyberPower ST900U | |
|---|---|---|
| Power | ||
| Rated apparent power | 850 VA | 900 VA |
| Rated real power | 450 W | 500 W |
| Topology | - | Standby |
| Battery waveform | - | Simulated sine |
| Automatic voltage regulation | - | No |
| Battery and runtime | ||
| User-replaceable battery | Yes | - |
| Runtime at 100 W | 35 min | - |
| Outlets and features | ||
| Outlets | 9 (6 on battery) | 12 (6 on battery) |
| Format | Desktop | Desktop |
| Display | - | LED indicators |
| USB charging ports | Yes | Yes |
| Data port, software or network option | No | Yes |
| Warranty | ||
| Warranty | 3 years | 3 years |
| Connected-equipment guarantee | $75,000 | $125,000 |