If a computer takes minutes to boot and every program launch involves a pause and some clicking noises, it almost certainly has a mechanical hard drive. Replacing it with a solid state drive changes that machine more than any other upgrade available, including more memory, and it usually costs less than people expect.
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The short answer
First work out which type your computer takes. Older machines need a 2.5 inch SATA drive; anything from roughly 2017 onwards usually takes an M.2 NVMe drive, which is faster and smaller. Buying the wrong form factor is the main way this upgrade goes wrong. For an old machine, 1TB is the sensible size and the speed difference between good NVMe drives will be invisible to you.
Work out what your computer takes
- 2.5 inch SATA. A flat rectangle about the size of a pack of cards, connected by two cables. Every computer with a mechanical hard drive can take one. Limited to around 550 MB/s, which is still roughly five times faster than the drive it replaces.
- M.2 NVMe. A small stick that clips directly onto the motherboard. Much faster, no cables. Requires an M.2 slot, which most machines from 2017 onwards have.
- M.2 SATA. Same shape as NVMe, SATA speeds. Uncommon but it exists, so check what your slot supports.
If you are unsure, look up your exact model with the word specifications, or open the machine and look. A laptop with a removable bottom panel usually makes this obvious in two minutes.
On an old laptop with only one drive bay, check whether the optical drive can be replaced with a caddy that holds a 2.5 inch drive. That lets you keep the mechanical drive for files while booting from the SSD, and caddies cost very little.
The picks
Kingston NV3 1TB M.2 NVMe SSD
The sensible default for most upgrades. A gigabyte of capacity, PCIe 4.0 speeds, and a price that reflects the fact that most people will never notice the difference between this and a drive costing twice as much. For boot, applications and general use, the gap between a good value NVMe drive and a flagship one is measurable in benchmarks and invisible in practice.
WD_Black SN7100 1TB NVMe SSD
A step up that is worth the difference if you move large files or work with video. It is also notably efficient, which matters in a laptop where an NVMe drive sits under the keyboard with nowhere to shed heat. Good software for cloning and monitoring, which makes the upgrade itself easier.
Samsung SSD 990 PRO 2TB
The drive to buy if you are upgrading something modern and you want the best. On an old computer it is overkill, because the rest of the machine will be the bottleneck long before the drive is. Included because it is the right answer to a slightly different question, and because two terabytes is a comfortable amount of space.
PNY CS900 250GB 2.5 inch SATA SSD
For a genuinely old computer with no M.2 slot, a 2.5 inch SATA drive is the only option, and it still transforms the machine. This is about as cheap as it gets. The honest caveat is capacity: 250GB fills quickly once Windows and a few applications are on it, so treat this as the option for a secondary machine rather than a main one.
Silicon Power 1TB NVMe M.2 PCIe Gen3
If your machine has an M.2 slot but only supports PCIe Gen 3, there is no point paying for a Gen 4 drive that will run at Gen 3 speeds anyway. This is the right specification at the right price for that case, and a terabyte is a comfortable size.
What actually matters
Worth paying for
- The right form factor for your machine, which is the only truly critical decision
- At least 1TB, because filling an SSD past about 80 percent slows it down
- A brand with decent cloning software, which makes the upgrade far easier
- A five-year warranty, which most reputable drives carry
- DRAM cache on drives you will write to heavily
Not worth it
- Paying for Gen 5 speeds on a machine with a Gen 3 slot
- Very small capacities that you will outgrow in a year
- Unbranded drives with no warranty and no software
- Assuming sequential speed figures matter, when random performance is what you feel
- Buying the fastest drive for a machine whose processor is the real bottleneck
Doing the upgrade
- Clone rather than reinstall if you want to keep everything as it is. Most drive makers supply free cloning software, and you will need a USB adapter or enclosure to connect the new drive during the clone.
- A clean install is the better option if the machine is cluttered after years of use. You get the speed benefit and a tidy system at once.
- Back up first, whichever route you take. Cloning is reliable and it is still a moment where all your data is in one place.
- Keep the old drive in an external enclosure. It becomes a backup disk and it costs almost nothing.
- Check the machine boots from the new drive in the BIOS boot order before you put the case back together.
Check whether the drive is soldered to the board before ordering anything. Some modern thin laptops have non-removable storage, and no amount of buying will help. A teardown guide for your exact model will tell you in a minute.
How much faster is an SSD than a hard drive?
For boot and application launching, dramatically. Mechanical drives are limited by physically moving a head; a solid state drive has no moving parts and responds in a fraction of the time. It is the upgrade people describe as making an old machine feel new.
Do I need NVMe or is SATA enough?
For an old computer, SATA is enough and the difference will be hard to notice, because the rest of the machine limits it. Use NVMe if your machine supports it, since it usually costs the same now.
What size SSD should I buy?
1TB for a main drive. 500GB is workable if budget is tight, and 250GB fills up faster than people expect once the operating system and applications are installed.
Should I clone or reinstall?
Clone to keep everything as it is. Reinstall if the machine has accumulated years of clutter and you want a fresh start along with the speed.
Will an SSD help if my computer is slow for other reasons?
It fixes slowness caused by storage, which is most of it on an old machine. If the machine is short of memory or the processor is genuinely underpowered, an SSD helps but will not fix everything.
The bottom line
Identify the form factor your machine takes before anything else, because that is the only decision you can get truly wrong. Buy 1TB from a reputable brand with a five-year warranty, and do not pay for speeds your slot cannot use. Clone the old drive, keep it in an enclosure as a backup, and expect the machine to feel like a different computer.
