Samsung 840 Pro partial-fill 4k write performance (or lack of)... UPDATE Ooops, LOL

[Brahmzy]

I posted this on [H] a minute ago - hoping to get some feedback here.

So, after beating up my 2x 840 Pro 256 RAID0 array, I am less than impressed with the filled-drive 4K write performance. When I plugged these in, they were insanely fast. Faster than any other R0 set I've had yet. I mean installing the 100+ Windows Updates was just plain jaw-dropping to watch, lol.
I've got only about 240GB partitioned, out of 480, so half of the array is clean and clear, or should be. Granted I have dumped a lot of data on them (steam games etc) in the last day (about 100GB worth, including the OS), but I let the system idle overnight at a logon screen and this morning my write performance was about 1/3-1/4 of fresh clean drives.
This is WITH 50% over-provisioning with only about 1/3 of the array filled with actual data. I have never seen this happen with my Vertex 3 array, which these replaced. I am beginning to question the efficiency of the garbage collection on these drives. The array was built immediately after secure erasing both drives.
Regardless, with only half the array being partitioned, garbage collection shouldn't be a concern at this point - I have done very few deletions and have TRIM working on my P67 array via a modded BIOS. I also checked TRIM this morning and it appears to be working on this new array as well.
I wonder if I'm seeing a difference in write performance between a SandForce array vs. Samaung 840 Pro array? I have triple checked everything. 10hrs of inactivity should have been PLENTY of time for write performance to recover. I have heard that SF's GC is some of the best/most aggressive out of them all, and if that's truly what I'm seeing here, I might be returning these 840 Pros.

Has anybody else done any real-world heavy 4k writes on partially filled 840 Pros in a R0 array? What has your experience been?

I wonder if there's something that wasn't allowing the 840's to properly go into GC-mode during the night? I may try letting the box sit at the BIOS screen for a night.

UPDATE

Holy noob mistake. How long have I been doin this? Well over a decade now. Straight up didn't have write-cache turned on. I have no idea how this happened as I checked like THREE times. I think I was running off of 14hrs, staring at my screen jacking with crap.

It's all good now - sorry for the false alarm!

EMPTY


30% FULL, OS Volume

[Highendtoys]

You can read about it tomorrow at TweakTown on the 840 500GB. The next day the 250GB non-Pro goes live.

SF doesn't use heavy background GC, it is mainly just before the write. They have other tricks keeping the drives speedy Just hang tight and read my intro to the 840 tomorrow and you'll know why everyone says Samsung 830/840/840 Pro is so good.

[Ourasi]

Post an Anvilbench incompressible, and did you remember to enable WriteBack Cache after reinstalling windows?

[Brahmzy]

I'll get some screenshots up tonight. Yes, WC is enabled.

Yes, WC is enabled.

Uh, NO, it wasn't, dumbass.

[Ourasi]

Hihi...

I smelled this "rat" a loong way, and don't feel like a dumbass because the Inteldrivers have a tendency to report this on at the start, and after a reboot or two they kinda report the opposite all of a sudden. Sometimes I had to Enable - OK - Disable - OK - Enable - OK, just to make it stick, I run F6 drivers only.. Intel SSDTool has a tuner that tells you if it's on or off, ok to use to make sure...

Enjoy the 840pro, it might have a few reasons to get a FW update, but for that performance I'm tempted...

[Brahmzy]

Haha, yes. That write cache has bit me many times. Once you finally get it to stick, it's stuck for good. But, like you said, it may be a pesky bastage at array creation. The Pros are doing well - was workin' em most of the night. I'm glad the Vectors didn't blow em out of the water. Sounds like we 2 extremely similar offerings at the moment.