There are some discussions already about this, but I did some tests and found out strange results. As everybody reports, KXG50ZNV256G drive write speed reaches about 350MB/s in CristalDiskMark, despite information on Toshiba site, which says it should reach 1000MB/s. I tried OCZ drivers, no change.
I decided to make a clean Windows installation, with NO drivers - in AHCI mode, no internet connection. With no addidtional drivers, only basic Windows i decided to test this drive in CristalDiskMark. Write speed reached 1000MB/s. I repeated test 3 times, every time it reached 1000MB/s. After installation of any Intel related driver max write speed is somehow limited to ~350MB/s.
What is going on? Where should I report that issue? What causes it?
Interesting find. It would be worth reporting on the Intel forums if you're inclined, perhaps with links to the existing threads about this issue on these forums. I'm curious whether other Inspiron 7577 owners with this SSD can confirm your results though, because I find it hard to believe that none of those people ever tried a clean install in AHCI mode. I've also never seen other reports of the Intel RST driver creating a bottleneck like that -- but I guess anything is possible. And actually, I didn't even realize the Intel RST driver would install on a system configured in AHCI mode since the RST controller isn't even involved with the NVMe interface in that configuration. You should just see the "Microsoft Standard NVM Express Controller" driver, or whatever it's called. How were you even able to replace that with an Intel driver?
I did not install Intel RST. I meant any Intel driver, but not related with drive, like Thermal Framework or Chipset. Installing any of these 2 (yes, I tried 2 clean installations) caused write speed limit at ~350MB/s. I did not try that procedure with other drivers. Maybe there is something wrong with drive firmware - I read that 512GB version has better speeds, but still not 1000MB/s. I hope someone with this configuration can test it out on with and without any drivers. It is not Windows 10 issue, at Windows 8.1 things look the same.
It's not interesting at all. I don't understand, how you can be "Dell Community Rockstar". We have another one interesting find too, you know. When you don't have nVidia or Intel drivers, nobody have notoriously known mouse stutter/freeze/right click lag. When you install those, some people just have problems. And nobody gives a f-uck about anything in Intel forums. They're trying to fix mouse stutters/freezes for months.
In short, Toshiba f-ucked up with firmware, that's all. No updates, we see the results. I will go for RMA soon. I can confirm that too: AHCI, no drivers - working as intended, same in Linux. Any drivers, Toshiba XG5 can't breathe. I don't want to use NVMe with 350MB/s Write and I will demand for Samsung one. The problem is in the XG5 firmware and Dells motherboard, because that NVMe looks great in reviews. Why? No Dell motherboard, of course.
I don't understand why me considering something interesting makes you skeptical of me being a Rockstar, but ok. I haven't been following the Inspiron 7577 saga specifically -- sorry if that offends you. I also didn't realize at the time of that post that any Intel driver introduces this slowdown, not just the Intel RST driver. But either way, even though I can certainly understand the frustration of Inspiron 7577 owners here, from a purely technical standpoint I do still consider it interesting that somehow that Toshiba SSD is able to perform reasonably before certain drivers are installed, even drivers not directly related to storage. I agree it's very likely a problem with the SSD's firmware, but it would be interesting to know what specifically causes the interoperability problem between the SSD and whatever is going on with Intel's drivers that doesn't occur before they're installed.
So, we have interesting findings and issues in this machine/its parts. But what do we do now? People from Dell Comunity are aware of that, but does it help? Are Dell's maintenance/technicians also aware of those issues? Can they somehow announce that they are working on those? Some progress, anything? As for now, we have main issues:
-Toshiba Drive low write speed
-Speakers (some people report crackling, I just can hear hiss when any media is paused, but not stopped, ex YouTube vide)
Optimus stuttering is not Dell-only issue, but it should be in their interest to fix that and they should exert pressure on Intel/Microsoft/Nvidia.
Someone asked for a tool to control fans speed in 7577 - I read that request was passed to technicians, but no news since then - it would be nice if there was a response, like "we will do this/we won't do this".
It's just lack of proper communication between users and maintenance and since that I have a feeling all those issues won't be resolved because nobody cares.
I mean, c'mon - this machine was released last year - nobody tested it before? With Windows?
Tomorrow this discussion thread will be on second page and everyone will forget it, so whatever.
7577 - wonderful machine which suffers from poor software.
So, I found an old discussion:
And at the end, according OP, Dell's Engineering Team stated that "drive's behavior is 'working as designed'" and that it's due to SLC buffer maxing out.
So, the drive is designed to reach maximum speeds with bare minimum Windows installations and slow down when drivers are installed? Why SLC buffer is not slowing down drive when there are no addtional drivers, but after installing any, it does?