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QNAP TS-251D vs QNAP TS-451D2
The quick verdict
- Spec leadeach leads on 3 of 6 differing specs
Rankings and scores come from the specs alone and are not affected by affiliate commissions.
Spec ruler
In short
Bottom line. Of the 6 specs that differ, the QNAP TS-251D leads on 3 (USB ports, weight, and volume) and the QNAP TS-451D2 on 3 (drive bays, boost clock, and LAN ports). On our small-office file server index, the TS-451D2 scores 40/100 against 26/100.
Using the 11 specs published on QNAP's official hardware specification pages, here is how the QNAP TS-251D and QNAP TS-451D2 compare. Drive bays: the TS-451D2 at 4 bays versus 2 bays for the TS-251D, 2 bays more (2.0x). Among 219 QNAP models, the TS-451D2 ranks in the bottom 35% and the TS-251D in the bottom 11%. The TS-451D2 leads on boost clock, 2.9 GHz to 2.7 GHz. Among 201 QNAP models, the TS-451D2 ranks in the top 39% and the TS-251D in the top 49%. On LAN ports, the TS-451D2 posts 2 ports and the TS-251D 1 port, a gap of 1 port. Among 219 QNAP models, the TS-451D2 ranks in the bottom 38% and the TS-251D in the bottom 8%. USB ports: the TS-251D at 5 ports versus 4 ports for the TS-451D2, 1 port more (1.2x). Among 219 QNAP models, the TS-251D ranks in the top 18% and the TS-451D2 in the top 35%.
Key differences 3
Drive baysTS-451D2 leads
- TS-451D2 4 bays vs the TS-251D at 2 bays
- the TS-451D2 has 2.0x the drive bays
- among 219 QNAP models: TS-451D2 in the bottom 35%, TS-251D in the bottom 11%
With 8 TB drives: 32 TB vs 16 TB raw
LAN portsTS-451D2 leads
- TS-451D2 2 ports vs the TS-251D at 1 port
- the TS-451D2 has 2.0x the LAN ports
- among 219 QNAP models: TS-451D2 in the bottom 38%, TS-251D in the bottom 8%
2 ports for link bonding or separate networks
VolumeTS-251D leads
- TS-251D 3.99 L vs the TS-451D2 at 5.8 L
- the TS-251D: 1.81 L smaller
- among 217 QNAP models: TS-251D in the top 9%, TS-451D2 in the top 17%
1.82 L smaller on the shelf
Key specs at a glance
| Spec | TS-251D | TS-451D2 |
|---|---|---|
| Drive bays | 2bottom 11% | 4WINbottom 35% |
| LAN ports | 1bottom 8% | 2WINbottom 38% |
| Volume | 3.99 LWINtop 9% | 5.8 Ltop 17% |
| Weight | 1.48 kgWINtop 6% | 2.09 kgtop 14% |
| USB ports | 5WINtop 18% | 4top 35% |
| Boost clock | 2.7 GHztop 49% | 2.9 GHzWINtop 39% |
Show every spec
| Spec | TS-251D | TS-451D2 |
|---|---|---|
| Drive bays | 2bottom 11% | 4WINbottom 35% |
| CPU cores | 2bottom 9% | 2bottom 9% |
| Boost clock | 2.7 GHztop 49% | 2.9 GHzWINtop 39% |
| Base RAM | 4 GBbottom 47% | 4 GBbottom 47% |
| Max RAM | 8 GBbottom 25% | 8 GBbottom 25% |
| Max LAN speed | 1 Gbpsbottom 22% | 1 Gbpsbottom 22% |
| LAN ports | 1bottom 8% | 2WINbottom 38% |
| M.2 slots | 0bottom 46% | – |
| PCIe slots | 1top 49% | – |
| USB ports | 5WINtop 18% | 4top 35% |
| Weight | 1.48 kgWINtop 6% | 2.09 kgtop 14% |
| Volume | 3.99 LWINtop 9% | 5.8 Ltop 17% |
| Operating power | 15.3 Wtop 6% | – |
| Warranty | 2 yrbottom 35% | 2 yrbottom 35% |
| Metric (0–100) | TS-251D | TS-451D2 |
|---|---|---|
| Performance percentile | 7.8WIN | 6.8 |
| Lightness percentile | 94.8WIN | 86.3 |
| Compactness percentile | 90.3WIN | 83.8 |
| Home media server fit | 72 | No data |
| Small office fit | 26 | 40WIN |
| 10GbE video editing fit | 22WIN | 1 |
| Low-power compact 24/7 fit | 80 | No data |
The details
How to choose
- Volume matters most → the TS-251D (3.99 L vs 5.8 L)
- Drive bays matters most → the TS-451D2 (4 bays vs 2 bays)
More TS-251D leads
- Weight: 1.48 kg vs 2.09 kg
- USB ports: 5 ports vs 4 ports
More TS-451D2 leads
- Boost clock: 2.9 GHz vs 2.7 GHz
Combined metrics
- Total built-in LAN bandwidth (sum of port speeds): TS-451D2 2 Gbps vs 1 Gbps
- Weight per bay: TS-451D2 0.52 kg vs 0.74 kg
- Memory headroom (max minus base): 4 GB on both
Same on both
- CPU cores 2, base RAM 4 GB, max RAM 8 GB
- max LAN speed 1 Gbps, warranty 2 years
Use-case scores
- Small-office file server: TS-451D2 40 vs 26
- 10GbE video editing: TS-251D 22 vs 1
Use-case scores are Specotomy's own index, computed by fixed rules from official manufacturer specs; they are not manufacturer scores.
FAQ
- Which has more drive bays, the QNAP TS-251D or the QNAP TS-451D2?
- The TS-451D2, with 4 bays against 2 bays for the TS-251D.
- Which is lighter, the QNAP TS-251D or the QNAP TS-451D2?
- The TS-251D, with 1.48 kg against 2.09 kg for the TS-451D2.