How to Choose an SSD: What Fits Your PC and What Actually Matters
An SSD (solid-state drive) is one of the simplest upgrades, and one of the easiest to get wrong: two drives that look almost the same can need very different slots. This guide covers what fits your PC first, then how to compare the rest.
RigFit shows specs and compatibility. We don’t run speed tests. Any speed here is a rated figure from a spec sheet or an interface limit, not something we measured.
The short answer
- For most desktop PCs built in the last several years, buy an NVMe M.2 2280 SSD. It plugs straight into the motherboard, with no cables.
- Match the PCIe generation to what your board and CPU support. A faster drive still works in a slower slot. It just runs at the slot’s speed.
- 1 TB is a sensible minimum for a gaming PC; 2 TB if you install a lot of large games.
- PCIe 4.0 is the value pick. PCIe 5.0 only pays off if your board has a PCIe 5.0 M.2 slot, and even then it costs more and runs hotter.
- No M.2 slot, or an older laptop? A 2.5-inch SATA SSD is still a big step up from a hard drive.
Will it fit and work?
This is the part most buying guides skip, and it is where most returns come from. Work through it in order.
1. M.2 or 2.5-inch SATA?
There are two shapes of SSD for desktops.
- 2.5-inch SATA SSD. The size of a laptop hard drive. It needs a SATA data cable to the motherboard and a SATA power cable from the power supply. SATA is the older connection, built for hard drives, and it tops out at 6 Gb/s (about 600 MB/s). Almost every desktop board has SATA ports.
- M.2 SSD. A small stick, about the size of a stick of gum, that screws onto the motherboard. No cables.
2. NVMe or SATA, even inside M.2
Here is the trap: M.2 is a shape, not a speed. An M.2 drive can talk to the PC in one of two ways.
- NVMe (Non-Volatile Memory Express) runs over PCIe, the same fast lanes a graphics card uses. This is what you want.
- M.2 SATA uses the old SATA connection in the M.2 shape. Same speed limit as a 2.5-inch SATA drive.
Some M.2 slots take only NVMe drives. Some older or budget boards have M.2 slots that take only SATA drives. Some take both. Your board manual says which, slot by slot. In our catalog of 923 drives, 38 are M.2 SATA, so they are uncommon but easy to buy by mistake.
You can often tell them apart by the notches (the “key”). NVMe drives normally have one notch, on the right (M key). M.2 SATA drives usually have two notches (B+M key). Desktop M.2 slots for SSDs are M key.
3. Length: 2280 is the standard
The digits after “M.2” are the size in millimeters. 2280 means 22 mm wide and 80 mm long, and nearly every desktop board takes it. You will also see 2230 (handheld gaming PCs, some laptops), 2242, and 22110 (some workstation boards). A shorter drive fits a longer slot only if the board has a screw post at that length; a longer drive never fits a shorter slot.
4. PCIe generation: the slot’s speed limit
PCIe comes in generations. Each one roughly doubles the bandwidth. A typical NVMe SSD uses four lanes (x4).
| Connection | Interface limit, roughly | Notes |
|---|---|---|
| SATA III | 0.6 GB/s | 2.5-inch and M.2 SATA drives |
| PCIe 3.0 x4 | 3.9 GB/s | Common on boards from about 2017 to 2020 |
| PCIe 4.0 x4 | 7.9 GB/s | Most current mid-range boards |
| PCIe 5.0 x4 | 15.8 GB/s | Only on some current boards and CPUs |
Rated drive speeds sit a little below these limits. The key rule: PCIe is backward and forward compatible. A PCIe 4.0 drive works in a PCIe 3.0 slot, at PCIe 3.0 speed. A PCIe 3.0 drive works in a PCIe 5.0 slot, at PCIe 3.0 speed. Nothing breaks; you just get the slower of the two.
5. Your CPU matters too, not only the board
Each M.2 slot is wired either to the CPU or to the chipset (the hub chip on the motherboard). The fastest slot, usually the top one, comes from the CPU. So the CPU can cap that slot. Two examples from our data:
- On AMD’s AM5 boards, the Ryzen 8000G and 8000F chips (such as the Ryzen 5 8500G and Ryzen 7 8700F) have PCIe 4.0, not 5.0. A PCIe 5.0 drive runs at 4.0 with them, even on a board with a PCIe 5.0 slot.
- On AM4, many APUs (the “G” chips, such as the Ryzen 5 5600G) and the older Ryzen 1000 and 2000 chips have PCIe 3.0.
Slots wired to the chipset are limited by the chipset’s own lanes. On AMD A620 and B840 boards, the chipset only has PCIe 3.0 lanes, so any extra M.2 slot it feeds runs at 3.0 at most.
6. Which boards have a PCIe 5.0 M.2 slot
| Socket | Every board has a PCIe 5.0 M.2 slot | Up to the board maker | No PCIe 5.0 M.2 slot |
|---|---|---|---|
| AMD AM5 | B650E, B850, X670, X670E, X870, X870E | B650 | A620, A620A, B840 |
| Intel LGA1851 (Core Ultra 200S) | none | B860, Z890, Q870, W880 | H810 |
| Intel LGA1700 (12th to 14th gen Core) | not in our data yet | ||
| AMD AM4 | none: PCIe 4.0 at most (and only with some CPUs) |
So “only some Z890 boards have a PCIe 5.0 M.2 slot” is real: it is the board maker’s choice. When a chipset is in the middle column, check the board’s spec page.
7. Shared lanes: when one slot turns off another
Boards have a fixed number of lanes, so makers share them. Common cases:
- An M.2 slot that disables SATA ports. Fill a certain M.2 slot and, say, SATA ports 5 and 6 stop working. If you also have a hard drive plugged in there, it disappears.
- An M.2 slot that slows the graphics card slot. On some boards, using a particular PCIe 5.0 M.2 slot drops the main graphics slot from x16 to x8.
- Two M.2 slots sharing lanes, so filling both makes one run at x2 instead of x4.
These are board-specific, and only the board manual lists them. Look for a table named something like “M.2 and SATA sharing” or footnotes under the storage specs.
8. Heatsinks and clearance
A heatsink is a metal cover that pulls heat off the drive. Many boards include one for each M.2 slot; some drives come with their own. If both exist, use one, not both stacked. PCIe 5.0 drives run warm enough that a heatsink matters. Check that a tall drive heatsink won’t hit your graphics card, since the top M.2 slot often sits right under it.
What our checker covers today
| Check | RigFit checks it | Check it in your board manual |
|---|---|---|
| NVMe vs SATA drive, and the PCIe generation to buy | Yes | |
| CPU’s PCIe generation capping the drive | Yes | |
| Whether the chipset gives a PCIe 5.0 M.2 slot (yes, board-dependent, no) | Yes | |
| Whether the board’s chipset has SATA ports at all | Yes | |
| How many M.2 slots and SATA ports your exact board has | Yes | |
| Which lengths fit (2230, 2280, 22110) | Yes | |
| Whether an M.2 slot takes SATA drives, NVMe drives or both | Yes | |
| Lane sharing (slots that disable SATA ports or slow the GPU slot) | Yes | |
| Heatsink clearance under your graphics card | Yes |
How much space do you need?
| Use | Suggested size | Why |
|---|---|---|
| Office, browsing, school | 500 GB | Windows 11 needs at least 64 GB, plus updates and apps |
| Gaming PC, main drive | 1 TB | Many large games list 100 GB or more on their store pages |
| Big game library | 2 TB, or 1 TB plus a second drive | Avoids constant uninstalling |
| Video, photos, large projects | 2 TB to 4 TB | Raw footage fills drives quickly |
| Bulk archive, backups | A hard drive (HDD) | Cheaper per terabyte, slower |
Leave some room free. SSDs slow down and wear faster when they are nearly full, so plan to fill no more than about 80 to 90 percent.
What the specs mean
Rated sequential read and write (MB/s). How fast the drive moves large files in one stream, in ideal conditions. It is the big number on the box. Rated, not tested, and it only shows when copying big files.
Random read and write (IOPS). How fast the drive handles lots of small pieces, which is most of what Windows and games do. It matters more for everyday feel than the sequential number, but makers measure it in different ways, so compare it with care.
DRAM cache vs HMB. Many SSDs have a small memory chip (DRAM) that holds a map of where data lives. Cheaper “DRAM-less” NVMe drives use HMB (Host Memory Buffer): they borrow a little of your PC’s own RAM for the map. For a gaming or home PC, a good HMB drive is fine. For heavy, sustained writing, DRAM helps.
TLC vs QLC. This is how many bits each memory cell stores: TLC holds three, QLC holds four. QLC packs in more space for less money, but it usually has lower endurance. Most drives use part of their free space as a fast write cache, and QLC drives slow down most once that cache fills during a long write. TLC is the safer default; QLC is reasonable for a game library you mostly read from.
Endurance (TBW) and warranty. TBW (terabytes written) is how much data the maker promises you can write before the warranty ends. Typical home use writes far less than most ratings. Treat TBW and the warranty length (often 3 or 5 years) as a sign of how much the maker trusts the drive.
Is PCIe 5.0 worth it?
For most people, not yet. Here is the honest trade-off.
- You need the whole chain. A PCIe 5.0 CPU and a board with a PCIe 5.0 M.2 slot. Miss either and the drive runs at 4.0.
- It costs more per terabyte than a good PCIe 4.0 drive. The same money often buys twice the space at 4.0.
- It runs hotter. Plan on a heatsink, and check clearance.
- The gain shows mostly in big file copies. We don’t test speed, so we won’t promise faster game loads. Rated numbers don’t tell you how a drive feels day to day.
It makes sense if you already have the platform, you move very large files often, and the price gap is small. In our catalog, 39 of 481 NVMe drives are PCIe 5.0, from 512 GB to 8 TB.
How to compare two drives: a checklist
- Fits: same form factor (M.2 2280 or 2.5-inch) and the interface your slot takes (NVMe or SATA).
- PCIe generation: no faster than your slot and CPU allow, unless the price is the same.
- Capacity: compare price per terabyte, not price per drive.
- Memory type: TLC or QLC.
- DRAM or HMB.
- TBW and warranty years.
- Heatsink: included or not, and whether it fits under your graphics card.
- Exact model number. Makers sometimes change parts inside a drive without changing its name. Note the full model code and check the current spec sheet.
Replace your main drive or add a second one?
Adding a second drive is the simple route. Install it, format it in Disk Management, and put games or files on it. Windows stays where it is.
Moving Windows to the new drive takes more steps: clone the old drive (many SSD makers offer free cloning software for their drives) or do a clean install of Windows. Back up first either way, then set the new drive first in the BIOS boot order.
Common mistakes
- Buying an M.2 SATA drive for an NVMe-only slot, or the reverse.
- Paying for PCIe 5.0 on a board or CPU that runs it at 4.0.
- Filling an M.2 slot that turns off the SATA port your hard drive uses.
- Losing the tiny M.2 screw. It usually comes with the board, not the drive.
- Stacking a drive’s own heatsink under the board’s heatsink.
- Thinking a new drive is dead when it just needs to be initialized and formatted in Disk Management.
FAQ
Will any NVMe SSD work with my motherboard? Only if your board has an M.2 slot that takes NVMe drives, and the drive’s length fits. The PCIe generation won’t stop it working; it only sets the speed.
Can I put a PCIe 4.0 SSD in a PCIe 3.0 slot? Yes. It works and runs at PCIe 3.0 speed.
Is NVMe better than SATA? For a desktop with an NVMe slot, yes: the interface allows several times the bandwidth of SATA, usually for a similar price. SATA still makes sense for PCs without M.2.
Do I need a heatsink for my SSD? For PCIe 5.0 drives, yes. For PCIe 4.0 drives, it helps and most boards include one. For PCIe 3.0 and SATA drives, usually not.
How many SSDs can I install? As many as your board has M.2 slots and SATA ports, minus any that share lanes. Your board manual lists both.
Is a DRAM-less SSD bad? No. A DRAM-less NVMe drive with HMB is fine for gaming and everyday use. DRAM helps most with long, heavy writing.
See which SSDs fit your PC
Tell us your motherboard and CPU, then the size you want and whether you want best value or as fast as your PC allows. We tell you which drive to look for: NVMe M.2 2280, and the PCIe generation your board and CPU support.