NVMe SSD speed tests wanted - Page 1
Forum section: electronics / projects

author: Wilson__
author_rank: Frequent Contributor
timestamp: January 03, 2025, 03:03:26 am
content: Need some read speed data before buying NVMe SSD drive for Linux1. df for device name, /dev/nvme0n12. hdparm command as inhttps://webhostinggeeks.com/howto/how-to-check-disk-read-write-speed-in-linux/3. post speed (400 to a few thousands), brand/model of NVMe SSD disk, size TB, PCIe generation (2 to 4 or 5), CPU, RAM, Linux Distro name/version----------$ dfFilesystem 1K-blocks Used Available Use% Mounted on/dev/nvme0n1p2$ sudo hdparm -t --direct /dev/nvme0n1/dev/nvme0n1:Timing O_DIRECT disk reads: 1222 MB in 3.00 seconds = 407.32 MB/sec$sudo hdparm -t /dev/nvme0n1/dev/nvme0n1:Timing buffered disk reads: 1254 MB in 3.00 seconds = 417.55 MB/sec

author: Wilson__
author_rank: Frequent Contributor
timestamp: January 03, 2025, 03:23:12 am
content: Samsung 990 PRO is PCIe gen 4, 4 lanes, rated 7450 GB/s.May be 5000 to 6000 in real system???https://semiconductor.samsung.com/consumer-storage/internal-ssd/990-pro/

author: garrettm
author_rank: Frequent Contributor
timestamp: January 04, 2025, 09:30:15 am
content: I have a Samsung 990 2TB connected via PCIe 4.0 and I get around 6.7 GB/s read speed on the main BTRFS partition with compression turned on (zstd level 1).NVMe drives are very fast, even PCIe 3.0 drives. The main thing to watch out for is drive endurance and if there is an SLC cache being used to "boost" benchmark performance. Lesser NVMe SSDs' performance falls off a cliff after 128 GiB or so of writes. Others overheat and radically reduce in performance to keep temperatures down.You will want a motherboard with integrated heatsink or a PCIe to m.2 adapter card with heatsink to avoid throttling.If you want to go 4Kn, don't buy Samsung: they are stuck with 512e on their desktop/laptop drives while Western Digital drives can be reconfigured for 4Kn.NVMe namespaces are pretty cool, but non-enterprise/server SSDs only allow for one namespace.Some problems I've encountered with Linux is ASPM causing "correctable" errors for some of my NVMe drives... The issue isn't simple to diagnose and the Z590 PCH looks to be part of the problem. Anyways, your mileage may vary with respect to power savings on a desktop system. For mobile, my Tiger Lake laptop with WD NVMe drive works fine with ASPM enabled.

author: Haenk
author_rank: Super Contributor
timestamp: January 05, 2025, 08:50:48 am
content: What a silly request.The true speed very much depends on a) your system and b) your workload - there is not "one parameter describes it all".So - first step is to describe your usage (consumer or server use should be stated as well) and system, second step is to define a budget.If you want one rule of thumb: Get the most expensive $ per GB branded, currently in production, SSD, they are usually priced high for a reason.

author: Wilson__
author_rank: Frequent Contributor
timestamp: January 05, 2025, 01:07:32 pm
content: Quote from: garrettm on January 04, 2025, 09:30:15 ammany thanks. 6.7GB/s is 90% of the rated (for 990 PRO) and really nice. May I ask which CPU is used? To get 90% of rated speed meaning CPU is not bottleneck compare with the SSDMy learning Linux machine is 400MB/s PCIe gen2, 1 lane. Perfect for daily web browsing and office work.Explaining Computing has a video on endurance and cliff fall off after buffer RAM used up in write. The MZ-V9P2T0BW (2TB) is 5-year or 1200 TBW limited warranty. (TB Written)May I ask what is 4Kn vs 512e and namespace?

author: Wilson__
author_rank: Frequent Contributor
timestamp: January 05, 2025, 01:17:09 pm
content: Many thanks. True.

author: garrettm
author_rank: Frequent Contributor
timestamp: January 06, 2025, 08:45:04 am
content: My CPU is an Intel 11900T (11th Gen Rocket Lake) with 128GiB DDR4 3600MT (fastest RAM for the density). Both of my PCIe 4.0 NVMe drives (Samsung 990 Pro and WD_BLACK SN850X) are connected directly to the CPU's PCIe lanes via an 8x PCIe to two slot m.2 add-on card using PCIe bifurcation for a 8x / 4x+4x lane configuration for the two PCIe 16x slots. A DDR5 system could probably get better compression performance, when not CPU limited. A big factor with compression is the CPU power governor: power-save, balanced, and performance. The power-save governor will hinder both compression and NVMe performance. Another factor is the hash algorithm used on BTRFS, the default is CRC32 which bench marked as the fastest on my system (which uses Intel's optimized CRC32 algorithm), but xxHash is competitive and could be faster on non-x86_64 systems or older x86_64 CPUs.https://github.com/Cyan4973/xxHashEnabling xxh hash for BTRFS takes some extra work though. So I wouldn't recommend it unless you are trying to optimize your system for maximum performance. And... are using BTRFS with compression enabled. Otherwise there isn't a point to even ponder this further.Namespace is feature that allows NVMe storage to "partition" the flash media in such a way that the OS sees two physical drives. It is also used to overprovision a drive to increase write endurance (by leaving 10% or so of the flash outside a namespace). Using two namespaces can simplify dual booting Windows and Linux on a single SSD (as if there were two physical drives) or create a safe area to store user data that won't be affected by reformatting the namespace that contains the OS when changing from Windows to Linux (or vice versa). It's a very useful and powerful feature that is not available with SATA or SAS drives. I'm actually looking forward to NVMe hard drives with the ability to use namespaces. It would allow for some interesting options for external drives used to boot different OSes/Ventoy and contain a stable data area that isn't affected when the other namespace is reformatted.4Kn stands for 4kiB "native" sector size. Legacy storage media used 512 byte sector size. Around 2010 "Advanced Format" drives became available as 512e or 512 byte emulated sectors on 4 kilobyte native sector drives. An OS that doesn't write integer multiple of 4kiB for the allocation unit will run into "write amplification" because it will perform multiple writes to the same physical sector on an Advanced Format storage device. Modern OSes have workarounds for this issue, but legacy OSes require 512e to work properly. Anyways, you can look this up if you want more info on the topic. There is a small performance improvement when enabling a 4Kn namespace for supported OSes (such as modern Linux and Windows since 8.1), but it isn't something you should mess with unless you know what you are doing.

author: garrettm
author_rank: Frequent Contributor
timestamp: January 06, 2025, 09:01:44 am
content: I realized I didn't actually test the BTRFS partition in my first post...I've attached new tests for both the main BTRFS partition and the "whole drive".BTW, these tests are with _a lot_ of apps running in the background (firefox, music player, terminal apps, etc.).

author: tinymini
author_rank: Contributor
timestamp: January 07, 2025, 11:36:06 am
content: Anandtech used to be my go to for such benchmarks ... until they went away. (only archives are left)If you want to know how to "properly" test a drive's performance, read their article for SK hynix's gold P31 SSD - although 4 years old, one of my favorites.https://www.anandtech.com/show/16012/the-sk-hynix-gold-p31-ssd-reviewAlso, while I love this forum, these questions should be better asked onlevel1techs(L1T)orServeTheHome(STH)forums.As a beginner you might prefer starting with L1T. Not because STH is unfriendly, but they're more geared towards server and enterprise.If you REALLY need special performance, here's some tldr for looking what kind of drive you need:If you're just looking for burst writes or fast sequential reads, usual name-brand consumer nvme drives are probably good enough.Sequential read speeds tend to not deviate that much from manufacturer claims.Just don't forget to update the firmware on samsung drives.(for Chinese brands, look for YMTC 232 layer chips - they were made for apple and are pretty nice)If you want good sustained writes (as in, same write speed even when the drive is almost full) or large capacity, look for used enterprise SSDs on ebay.They aren't that expensive compared to consumer drives, esp. >4TB.Just know that you might need an M.2 to U.2 adapter, or even better - an pcie to M.2 adapter.They are also very good at write endurance - usually rated with DWPD (drive writes per day) * warranty years.(Yes, you can literally write petabites on them)If you want really low latency or insane write endurance, optane is your friend. While they're discontinued by intel, 2nd hand stock is still on ebay.They are somewhat between RAM and SSDs - expensive for bulk storage but your only option if you really need it.(I think datacenters moved away from them due to CXL maturing, but I don't know)