Storage is the component where benchmark figures diverge most sharply from how a machine actually feels. A drive twice as fast on paper is rarely twice as fast to use, and knowing which specifications matter saves real money.
In short
- Any solid state drive is transformative compared with a mechanical one. The differences between SSDs are far smaller.
- Capacity and reliability matter more than sequential speed for most people.
- A DRAM cache matters for sustained large writes, not for gaming or general use.
- Check how many M.2 slots your board has and what filling them disables.
Why sequential speed is the wrong headline
The large numbers on the box are sequential read and write: how fast the drive moves one enormous contiguous file. Copying a video file does that. Very little else does.
Booting, launching applications and loading a game are dominated by small random reads scattered across the drive. Every SSD is vastly better at those than a mechanical drive, and the differences between SSDs are comparatively small. This is why a PCIe 5.0 drive quoting figures twice those of a PCIe 4.0 drive does not boot twice as fast, or noticeably faster at all.
DRAM cache, and when it matters
Drives maintain a map of where data physically sits. Some hold that map in dedicated DRAM on the drive; cheaper ones borrow system memory or keep it in slower flash.
The difference appears under sustained heavy writes and when the drive is nearly full. Writing hundreds of gigabytes continuously, a DRAM-less drive slows substantially once its fast cache region is exhausted.
For gaming and general use, this rarely shows up. For video work or anything writing large volumes regularly, it is worth paying for.
Endurance figures
Drives are rated in terabytes written, the total that can be written over the drive life. The figures look alarming until you compare them with actual use.
A typical desktop writes a few terabytes a year. A drive rated for 600 TBW at that rate has a life measured in decades. Endurance is a real consideration for write-heavy professional work and essentially irrelevant for normal use.
Leave it some room
Solid state drives slow as they fill, because the fast cache region shrinks and there is less space for wear levelling to work with. Keeping a drive below roughly 80 percent full avoids this. Our storage planner accounts for it.
The write cache and what happens when it runs out
Most consumer drives write incoming data to a fast cache region first, then move it to slower, denser storage in the background. This is why a drive can quote very high write speeds that it cannot sustain.
Copy 20 GB and you will likely stay inside the cache and see the advertised figure. Copy 200 GB continuously and the cache fills, the drive falls back to writing directly, and the speed can drop by a large factor, occasionally below what a mechanical drive manages.
This matters for video work, large game installs and bulk transfers, and is irrelevant for everyday use. The cache also shrinks as the drive fills, which is another reason to leave free space.
Reviews that run sustained write tests will show this behaviour. A specification sheet will not.
PCIe 5.0 drives, and whether you need one
For most people, no. The sequential figures are impressive and everyday use is dominated by small random reads where the difference is minimal.
They also run considerably hotter, frequently requiring a substantial heatsink and sometimes a fan, and they cost more. A drive that throttles because it cannot shed heat is slower than a cooler PCIe 4.0 drive.
The case for one is specific: sustained large sequential transfers, or professional work where the throughput is genuinely used. Gaming is not that case, despite the marketing.
Before buying a second or third M.2 drive, check the board manual for lane sharing. Filling an additional M.2 slot commonly disables two SATA ports, and finding that out afterwards means unplugging something that was working.