Comparing five PCIe 4.0 SSDs

The PCIe 4.0 standard is slowly being replaced by PCIe 5.0. However, due to a lack of slots for the new type, the «old» version is still a good alternative. That’s why I’m testing the current top models from five manufacturers. Even though they offer similar specifications, they all have their strengths and weaknesses. I’ll tell you which SSD is the best all-rounder and which is particularly suitable for Office apps or gaming. I’m taking a close look at the following models:

• Samsung 990 Pro
• Crucial T500
• WD Black SN850X
• Corsair MP600 Pro NH
• Kingston Fury Renegade

The technical details

I’m testing the 2-terabyte (TB) version of every SSD. This is important because certain models have different specifications depending on memory size. For example, it’s common practice to install one gigabyte (GB) of DRAM per TB of memory. Things such as data allocation tables, which record logical blocks and their positions in the memory, are stored here. So if you buy an SSD I tested with more or less memory, there may be differences in the specifications.

Differences between the SSDs include the installed NAND flash memory and the controller. Samsung and Western Digital produce the latter themselves, while the other brands use Phison. When it comes to flash memory, everyone relies on TLC NAND. NAND is a non-volatile memory technology that doesn’t require power to store data. TLC stands for Triple Level Cell. This means 3 bits are allocated per memory cell. Samsung manufactures memory itself, Western Digital relies on BiCS from Kioxia. The other manufacturers use Micron flash memory.

The differences in read and write speeds are small. They’re more noticeable looking at terabytes written (TBW). This refers to the number of TB that an SSD can write in its lifetime. They’re usually conservative values. As a rule, drives can usually manage more. But even the lowest value of 1,200 TBW is more than sufficient. This’d allow you to write 1 TB of data per day for over three years – an unrealistic scenario for most people. Kingston promises by far the most with 2,000 TBW. However, the value says nothing about the actual durability of the device, only that Kingston is simply more generous here.

Reading: only minor differences

I measure read speeds with the CrystalDiskMark program. This shows that any differences between the SSDs in sequential reading are small. In random reading, the Samsung and Crucial SSDs – and at 80 per cent full Corsair too – perform significantly worse than Kingston and Western Digital.

The first value per SSD in the graph refers to sequential reading. The second value, on the other hand, refers to random reading and writing. If you work with large files, the first will be relevant for you. But if you use small files, you'll want to look at the second.

Even if the differences here are small, I’d go for Kingston or Western Digital in the read category, they deliver the best values.

Writing: no clear winner

Writing results are similar to reading. Any differences particularly stand out when writing randomly in CrystalDiskMark. The Corsair SSD shows varying performance empty versus 80 per cent full. With less available space, the sequential write speed is reduced by 1,000 megabytes per second.

In a practical test, I copy a 10-gigabyte file from a RAM disk to the SSDs. The RAM disk ensures that the SSD is the bottleneck, as the disk can achieve a much higher write and read rate. I don’t measure any differences between the fill levels in this test. The fact that the Corsair SSD suffers no drop here is due to the sequential writing used with the test file. In this case, the Corsair also had no drop in CrystalDiskMark.

To test how the SSDs behave when writing data continuously, I repeatedly write the 10 GB test file from the RAM disk to the SSDs using a batch command. This allows me to determine when they start to throttle down. The Samsung and Corsair SSDs are the first to apply the handbrake. After 200 GB of written data, the speed drops to 1,300 MB/s for Corsair and 1,500 MB/s for Samsung. The Western Digital and Kingston SSDs last longer. Here, the speed drops to 1500 MB/s after 500 GB of written data in both cases. The Crucial SSD lasts the longest during continuous writing. Only after 600 GB of written data does it throttle down, initially to 2.6 GB/s. After 700 GB of written data, only 120 MB/s are possible.

If I write continuously at 80 per cent full, maximum speed only lasts for 40 to 60 GB of written data. This happens because SLC mode is shorter at higher fill levels.

Based on the tests, I advise you use the Western Digital SSD. Not only is it fast, it also maintains high speeds for a relatively long time and doesn’t slow down too much.

Copying: only Corsair falls off

When copying, i.e. reading and writing to the SSDs at the same time, I duplicate the 10 GB file on the SSDs. Here, the Samsung SSD takes the lead when empty and at 80 per cent full. The differences between Kingston, Western Digital and Crucial are small. Only the Corsair slows down its copying speed significantly at 80 per cent full.

Based on these test results, the Samsung SSD wins.

Office: only Crucial lags behind

In Office applications, Samsung is once again at the top. When empty, only the Crucial SSD can keep up. However, as soon as it’s 80 per cent full, it falls behind and achieves similar results to the other SSDs.

Gaming: Crucial suffers again at high fill level

In the 3DMark gaming benchmark, the Western Digital SSD comes out on top by some distance. The SSDs from Kingston and Samsung are consistent both when empty and when 80 per cent full. Corsair and Crucial’s SSDs show greater losses at higher fill levels.

Western Digital wins the race for best all-rounder

Overall, the SN850X from Western Digital performs best in the tests. It won out in three categories, reading, writing and gaming, and can at least keep up when it comes to copying and Office apps. The Corsair SSD performs the worst.

However, the differences between these SSDs are small. You won’t notice them, especially when working with Office. Loading times in games are also very similar. You’ll only notice a small difference if you have to write huge amounts of data. So if you have a Corsair MP 600 Pro NH installed, you don’t have to switch to the test winner.

The Samsung SSD took second place, closely followed by the Kingston SSD. Crucial would also have scored well, but loses the most performance at a fill level of 80 per cent.