Gen5 vs Gen4 SSDs for AI Work: What the Read Speeds Say
Storage speed is the unglamorous spec that decides how an AI box feels. Loading a 40 GB model from disk, shuffling a dataset, writing checkpoints: all of it waits on the drive. This directory carries 140 storage products, and the SSDs that publish a sequential read figure split cleanly into Gen5 and Gen4 camps. Here is what the spec sheets actually say.
Gen5 flagships read at up to 14,900 MB/s on paper, roughly double the 7,000 to 7,450 MB/s ceiling of the best Gen4 drives. In model loading terms, a 40 GB checkpoint is about 3 seconds of pure read on a Gen5 drive at full tilt against about 6 on Gen4, before filesystem and decompression overhead takes its share of both. For dataset work the gap shows up less in single big reads and more in sustained mixed loads, where Gen5 drives also tend to carry bigger endurance ratings in this dataset.
Fastest published reads, Gen5 and Gen4
| Drive | Interface | Read up to | Capacity | US list price |
|---|---|---|---|---|
| Crucial T710 1TB | Gen5 | 14,900 MB/s | 1 TB | $200 |
| Crucial T710 2TB | Gen5 | 14,900 MB/s | 2 TB | $354 |
| Crucial T710 4TB | Gen5 | 14,900 MB/s | 4 TB | $700 |
| Western Digital WD Black SN8100 1TB | Gen5 | 14,900 MB/s | 1 TB | $240 |
| Western Digital WD Black SN8100 2TB | Gen5 | 14,900 MB/s | 2 TB | $435 |
| Samsung 990 Pro 1TB | Gen4 | 7,450 MB/s | 1 TB | $260 |
| Samsung 990 Pro 2TB | Gen4 | 7,450 MB/s | 2 TB | $499.50 |
| Samsung 990 Pro 4TB | Gen4 | 7,450 MB/s | 4 TB | $800 |
| Samsung 990 Pro with Heatsink 2TB | Gen4 | 7,450 MB/s | 2 TB | $527 |
| Crucial T500 1TB | Gen4 | 7,400 MB/s | 1 TB | $260 |
Peak read speed, top drives
The honest caveats: these are manufacturer peak sequential figures, the number least likely to describe your Tuesday. Gen5 drives also run hot and want a heatsink and airflow, which matters in small cases and mini PCs, and many laptops and boards cap the slot at Gen4 speeds anyway. If your board is Gen4, the fastest Gen4 drive is the rational buy and the price difference funds RAM instead.
Rule of thumb from the data: Gen5 for a new workstation build with the slot and the cooling to feed it, Gen4 for everything else, and capacity before speed once you pass 7,000 MB/s, because models and datasets only grow. Browse both camps on the storage page.