The NZXT H9 Flow wins in 7 out of 8 comparable specs. Its biggest advantage is Max Cooler Height (200% better).
A4-H2O wins in 1 spec (MSRP: 21% better).
Recommendation
Choose H9 Flow if you want the best overall performance — especially max cooler height.
Choose A4-H2O if msrp matters more to you.
| Spec | Lian LiA4-H2O | NZXTH9 Flow |
|---|---|---|
| Design | ||
| Type | Mini ITX | ATX Mid Tower |
| Side Panel | Tempered Glass | Tempered Glass |
| Weight | 3.5 | 10.2 |
| Compatibility | ||
| Max GPU Length | 322 mm | 435 mm+35% |
| Max Cooler Height | 55 mm | 165 mm+200% |
| Max PSU Length | 130 mm | 185 mm+42% |
| Max Radiator |
| 240 mm |
| 360 mm+50% |
| Motherboard Support | Mini ITX | ATX, Micro ATX, Mini ITX |
| Cooling | ||
| Included Fans | 0 | 4+100% |
| Storage | ||
| 2.5" Bays | 3 | 4+33% |
| 3.5" Bays | 0 | 2+100% |
| I/O | ||
| Front I/O | 1x USB-C, 1x USB-A 3.0 | 1x USB-C, 2x USB-A 3.0, Audio |
| Price | ||
| MSRP | $130−21% | $165 |
| Release Date | Jan 2022 | Jan 2023 |
