Not all SSD are created equal

Firstly, I would like to setup context. Few years ago, in company where I work decided to upgrade 256GB SSD to better ones. I did research and found that 512GB Samsung 850 EVO. This is great SSD and it works quite well for like 4 years. But eventually it filled up and I had to move some stuff to HDD and finally I decided enough is enough and ask our IT department to buy 1TB disk. I specifically asked for 860 EVO 1TB disk. After one week I got my disk and was happy user since.

Later I was asked to investigate problem with checking out data from one of our source control servers. At the same time, I got new PC. It has 9900K CPU and 1TB Samsung 970 Pro NVME SSD. And to my surprise new machine does checkout more than 2 times faster. This checkout process is not particularly CPU or disk intensive and started investigation.

At the end of investigation, I found that IT department bought me 1TB Samsung 960 QVO and I decided to check its performance with Samsung Magician. This is utility developed by Samsung to check and maintain their SSD drives. And here is performance of 1TB Samsung 960 QVO:

As you can see it has extremely slow write speed. In fact, so slow that it made me to test my old trusty 1TB Western Digital HDD. Here are results:

And as you can see HDD sequential write speed is 23% faster than write speed of SSD. I even go ahead and repeat checkout onto HDD and result is just little bit slower than on 1TB Samsung 960 QVO. 31 minute and 20 seconds on HDD vs 29 minutes and 40 seconds on SSD. HDD is still much slower than SSD in random writes.

Just in case checkout will create about 32GB directory that contains a 160K files and 20 000 directories. It is roughly 17 megabytes per second on write. It doesn’t look much even for HDD and yet performance is quite bad on HDD and QVO SSD.

Here are tests for 512GB Samsung 850 EVO:

I did run checkout test on this disk and 512 GB 850 EVO is exactly the same as 1TB Samsung 970 Pro. Actually 850 EVO was a bit faster but it was absolutely empty, so I think if I would fill it about 20% results will be a bit slower.

Here are tests for 512GB Samsung 860 EVO:

This is my home disk and I cannot provide results for it but I think it will be a bit slower than 850 EVO.

Here are tests for 1TB Samsung 970 Pro:

Disclaimer: These screenshots are from 3 different machines but for HDD I did run it on 2 different machines and results are the same. So there could be differences but I do not expect big differences. All drives except 970 Pro are SATA disks and 970 Pro is NVME disk.

As conclusion I would not recommend buying 860 QVO for anything, especially considering price difference. 1TB 860 QVO costs $122 and 1TB 860 EVO costs $129. You will feel bad write performance everywhere starting from installing and updating Windows. I know that it has write cache that supposed to mitigate slow writes, but it will be quickly depleted when you write a lot of data. Read performance is not so great also and considering $7 price difference I think QVO should be avoided in all cases.

And second conclusion that old good 850 EVO is still able to compete with top SSD from Samsung.

I hope it will help someone.

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