Samsung 990 Pro Showing Lower Than Expected Write Speeds After Six Months and I Am Not Sure What Is Normal

JennyLeoTalk — Tue, 16 Jun 2026 20:53:58 GMT

I picked up a Samsung 990 Pro 2TB about six months ago as the primary drive for my main workstation and the initial performance was exactly what the spec sheet promised. Sequential reads and writes were hitting close to advertised numbers and the overall system responsiveness felt like a meaningful step up from the SATA SSD I was replacing.

Over the last couple of months however I have started noticing something that is making me question whether the drive is behaving normally or showing early signs of something worth worrying about. Sequential write speeds during large file transfers have dropped noticeably compared to where they were when the drive was new and sustained write workloads that used to stay consistently fast now show a significant speed drop after the first few gigabytes before recovering.

I understand that NVMe drives use SLC caching to handle burst writes and that performance drops when the cache fills are a known characteristic of most consumer drives. What I am less certain about is whether the cache exhaustion point arriving earlier than it used to is a sign of normal wear progression or something else.

The drive currently sits at around 65 percent capacity which I have read can start affecting available SLC cache size on drives that use dynamic cache allocation. Samsung Magician shows the drive health as good with no warnings but the software has always felt more reassuring than genuinely informative to me.

I have been looking at adding a secondary NVMe purely for scratch and temporary file workloads to take pressure off the 990 Pro and was comparing options through Amazon , Orange Hardwares like platforms , alongside a few other retailers. The price difference between Samsung's own lineup and alternatives at similar performance tiers is significant enough that I am genuinely unsure whether staying within the Samsung ecosystem is worth the premium at this point.

Has anyone tracked long term write performance on the 990 Pro specifically and found that cache behavior changes meaningfully as the drive ages or fills up?

Re: Samsung 990 Pro Showing Lower Than Expected Write Speeds After Six Months and I Am Not Sure What Is Normal

ddaniel51 — Wed, 17 Jun 2026 02:46:31 GMT

I run a Xeon based workstation with 2 9100 Pro's, 5ea 4TB 990 Pro's, and a Lesser 4TB WD 850X.

The most I've written to a single drive is 14.5 TB. The CPU runs about 3.5- 4 GHZ so it is not pushing the drives to max performance. The thing is so fast and trouble free I don't care if the cache is slipping a bit as housekeeping will take care of it.

Files transfer at GB rates, apps (A few monster games excepted) load instantly and life is good.

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Samsung 990 Pro Showing Lower Than Expected Write Speeds After Six Months and I Am Not Sure What Is Normal

Re: Samsung 990 Pro Showing Lower Than Expected Write Speeds After Six Months and I Am Not Sure What Is Normal