SanDisk Ultra 3D SATA 4TB vs Silicon Power Ace A55 4TB
Silicon Power Ace A55 4TB is at least the equal of the other on every measure that decides this, and ahead on at least one.
| Specification | SanDiskUltra 3D SATA 4TB | Silicon PowerAce A55 4TB |
|---|---|---|
| Capacity (GB) | 4000 | 4000 |
| Sequential read (MB/s) | 560 | 560 |
| Sequential write (MB/s) | 520 | 530better |
| Current best price | £389.99at Amazon.co.uk · captured 2026-09-14 | £309.99betterat Amazon.co.uk · captured 2026-09-13 |
| Price per TB | £97.50 | £77.50better |
| NAND type | tlc | tlc |
How these two compare
Sequential throughput
SanDisk Ultra 3D SATA 4TB reads at 560 MB/s and writes at 520 MB/s; Silicon Power Ace A55 4TB reads at 560 MB/s and writes at 530 MB/s. Both ride the SATA bus, which caps sequential transfer near 550 MB/s in either direction — the ceiling every SATA drive works against — so what more decisively separates them is sustained and random behaviour, the DRAM cache, and endurance.
Price
SanDisk Ultra 3D SATA 4TB is £389.99 (£97.50 per TB); Silicon Power Ace A55 4TB is £309.99 (£77.50 per TB).
NAND and warranty
On the flash itself: SanDisk Ultra 3D SATA 4TB uses TLC, and Silicon Power Ace A55 4TB uses TLC. NAND tiers count bits per cell — more bits pack more capacity into the same silicon but shorten write endurance and slow sustained writes, which is why QLC sits below TLC on lasting performance even when the sequential numbers match. SanDisk Ultra 3D SATA 4TB does not state one and Silicon Power Ace A55 4TB carries a 3-year warranty — the length the maker will stand behind the drive, and usually a proxy for the endurance it is rated to.
Which to buy
Against the other, Silicon Power Ace A55 4TB is even or ahead on every tracked measure and behind on none, which is the one case where the choice needs no compromise.
Common questions about this pair
- Which is faster, SanDisk Ultra 3D SATA 4TB or Silicon Power Ace A55 4TB?
- SanDisk Ultra 3D SATA 4TB reads at 560 MB/s and writes at 520 MB/s; Silicon Power Ace A55 4TB reads at 560 MB/s and writes at 530 MB/s. Both ride the SATA bus, which caps sequential transfer near 550 MB/s in either direction — the ceiling every SATA drive works against — so what more decisively separates them is sustained and random behaviour, the DRAM cache, and endurance.
- Which costs less per terabyte, SanDisk Ultra 3D SATA 4TB or Silicon Power Ace A55 4TB?
- SanDisk Ultra 3D SATA 4TB is £389.99 (£97.50 per TB); Silicon Power Ace A55 4TB is £309.99 (£77.50 per TB).
- Should you buy SanDisk Ultra 3D SATA 4TB or Silicon Power Ace A55 4TB?
- Against the other, Silicon Power Ace A55 4TB is even or ahead on every tracked measure and behind on none, which is the one case where the choice needs no compromise.