960 Pro 1TB performance has lowered/become tempermental
I received my 960 Pro 1TB about a month ago. When I first received it, it benched exactly as expected (3300-3500 read, 2100-2200 write, and all the randoms were fine). Keep in mind this was in CrystalDiskMark running a 1GiB test size.
Samsung Magician V5.0 had no trouble making the drive look excellent, either. 3500+ read, 2100+ write, 450,000+ random read and 360,000+ random write.
Fast forward to today: Randoms in both test programs seem fine. Sequentials have bombed, though.
CrystalDiskMark gets ~3000 read and ~2000 write (Not so bad), but Samsung Magician gets 2200-2500 read/1600-1800 write now.
If I bump the test size in CrystalDiskMark up to a large amount like 16 or 32 GiB, the sequentials bench reasonably (3400+/2000+), which is more confusing.
I have made zero bios changes, zero driver changes, and am running the same installation of Windows. The only difference I can figure is I have installed ~380 GiB worth of software and programs on the drive. This still leaves 570GiB of free space, so it should not affect it.
Is it a bad drive controller? Something wrong with my PC? Even more confusing that huge samples test fine, but the Samsung Magician test and smaller CDM samples are testing significantly lower than when the drive was new.
The fact that large samples test fine and small samples don't (I'm sure magician uses tiny sample sizes, which is why the test is so quick) makes me think somehow there's some latency occurring that didn't used to. That would affect small sample sizes but not so much on large ones.
Edit: A side note, I have tested it as the OS drive and booted into windows on another drive as a non-OS drive, which should eliminate any software or background process overhead on the drive time. I am also testing with the latest version of Samsung Magician and have the latest version 2.1 of Samsung's NVMe driver.