NVME ssd speeds in real life.

[super gnu]

Ive just upgraded to a samsung 950 pro (had it sitting around for a year, just got a mobo that will accept it)

got it sitting in a pcie adapter card in a pcie3 4x slot. i have it as my boot drive. it benchmarks very nicely well over 2GB/ sec sequential reads. 1.3GB/sec writes..

however after using my machine heavily for 2 days with hwmonitor running, ive noticed that it makes very little difference at all to software load times and file load/save operations.

in hwmonitor the peak transfer rate registered in 2 days of opening and saving 3gb max files,working in photoshop, web browsing, gpu rendering and saving stacks of exrs, was a touch over 300mb/sec, im not sure when it achieved that rate or for how long.. Watching it while saving a stack of exrs from the vfb, it peaked at 10mb/sec.. saving a huge max file it peaked at an impressive 5mb/sec

what gives?

i am a stubborn windows 7 holdout.. but running the latest samsung nvme drivers and magician software.. maybe newer versions of windows work better with nvme..? all in all, im a touch disappointed.

[benb32]

[Edit, just saw you are using the Samsung nvme driver]

Would do a few things first:
a) Turn off the write cache buffer flushing in Windows device manager for the drive (although, you should be using a UPS with this disabled),
b) Make sure you are using the Samsung nvme driver, not the Microsoft one. (Assuming there is a 64bit Windows 7 version...)
c) there are a few guides that recommend disabling some Windows services as well, but in my experience, makes little difference...

Windows 10 does most of these things for you, plus makes managing and getting more out of modern storage easier.

The above should help increase performance by 10-15%. The performance of your storage depends on not just the raw throughput, but also latency (how quickly the drive responds to a command). The latency of nvme is only a little quicker than SATA ssd. Most of the stats showing how quick a drive is are around the 100,000 - 250,000 input output operations per second IOPS. A quick mechanical drive is only around 150 iops. When many disk commands are issues simultaneously they get queued - the drive checks to see if it can process the read/write commands out of order to speed up the apparent iops. This makes benchmarks appear very quick when the queue depth is high (greater than 32 commands).

Firstly, the software issuing the commands needs to be written so as to send multiple read/write asynchronously without waiting for the for the first read/write to complete. Secondly, in the real world, the queue depth never really goes above 2 for standard not specific workloads. So the random read/write at a very low queue depth is more likely around 10,000 - 20,000. Use task monitor performance tab to look at the disk utilization. The percentage (near 100%) will give a good approximation to the disk usage being saturated, although the throughput may only be 10 MB/s .

In summary, the slow write speeds you are seeing will be due to the process that is writing to the disk being bound by a single threaded operation (which can't send out data quick enough and is a bottleneck), which also happens to involve lots of random reads and writes at a low queue depth.

As a side note, optane drives have an iops of over 250,000 at a queue depth of 1. However, even with an octane drive installed, it is possible for the cpu/memory/program efficiency to be the slowest link.

Hope this helps, Ben

[super gnu]

Thanks a lot Ben, some good suggestions and insight there i knew not to expect miracles, especially with boot times, but i thought at least saving and loading big files would be lightning fast... maybe i need to edit some uncompressed 8k video to benefit...

[benb32]

Yup! It would be lovely to think that all computers do, is copy large contiguous files between locations with serial reads and writes - in which case it should fly into GB/s territory.

Truth is real world usage is nothing like that. But as a consolation, runing from the 950pro is still quicker than most other ssd drives. It is just the difference between sata ssd and nvme ssd is not that huge (but in certain circumstances still a vast improvement). It will most likely be your start-up programs causing the slow boot, would expect the desktop to be showing after 20 seconds from cold boot - with the rest of the time being the loading of all the background programs.

Windows 10 is a bit better at reducing boot times than Win7.

[psanitra]

It depends a lot on what your daily tasks are. I spend half of my time in Houdini nowadays, and fast drive it`s absolute must. Even smaller projects can grow to TB easily. Most of the time i actually do large file read/writes instead of high IOPS. Single frame of explosion can be 100MB-2GB. But i totally agree with what Ben wrote, and average artist will usually profit more from good balance between IOPS vs speed.

[super gnu]

It depends a lot on what your daily tasks are. I spend half of my time in Houdini nowadays, and fast drive it`s absolute must. Even smaller projects can grow to TB easily. Most of the time i actually do large file read/writes instead of high IOPS. Single frame of explosion can be 100MB-2GB. But i totally agree with what Ben wrote, and average artist will usually profit more from good balance between IOPS vs speed.

yeah i was playing round with Houdini sand simulation last year.. man that software can eat ram and hard drive speed/capacity.. only project ive ever done where i was convinced 128gb ram would be pitifully insufficient, and i filled a 3TB hard drive with preview files without even trying.