[SOLVED] Storage write speed slowing down after a few seconds

Nov 15, 2015
5
0
4,510
0
Hey everyone,

I got a super weird issue and nothing has worked so far. So a bit of context:

I'm testing file transfer from my NAS to my PC. The problem I'm having, even after a fresh reinstall of Windows 10, is I'm getting maybe 40 MB/s (almost 500 Mbits/sec) when I transfer something FROM my NAS to my PC. But when I transfer something from my PC to the NAS, I'm topping 1 Gbps (105-110 MB/s). So in short, I'm a bit over 2x faster when I send to the nas than when I copy FROM the nas.

The way I know that it's not the NAS, is I got an HTPC in the same room hooked up to my TV, plugged in the same ASUS RT-86U router and it's doing about 110MB/s both ways without so much as a slow down. The PC itself is not as fast. Here are the specs for the problematic PC:

i7-6700k no overclock
16GB RAM
Asus Z170-A MB
Samsung 950 Pro (I get 2100 MB/sec read and 948 MB/sec write, so definitely NO bottleneck there...)

Here's what I've done so far:

Bought a PCIe Intel i210-T1 network card, exact same behavior compared to the intel i219 card that's on-board
Changed the network cable going to the RT-86U
Did all the configuration changes that are suggested everywhere (disable autotuning, disable large send offload, disable IPv6...)
Scratched my head a bit more...

It's worth noting that when the transfer FROM the NAS starts, it does start around 100 MB/s, then slowly goes down until it reaches 35-40 and then it stays at that speed until the end of the transfer. I thought it might be cache depleting itself but why would it, and why not from the start when I got the PC and installed Win10? Also worth noting, I get the exact same speed transferring to an older OCZ Vertex3 drive, which can handle much more than 100 MB/s still and gets the exact same 35-40 MB/s write speed coming from the NAS.

At this point, I've eliminated the Samsung drive as a bottleneck for sure. My Intel RST driver is up to date. Write cache is active on the two drives. Windows is up to date.

Now where it gets much weirder, is that from my Vertex 3 drive to my Samsung drive, I get about 50-60 MB/s where I should get the full speed of the Vertex 3 read (I suppose it should read at around 500 MB/sec, which is not a problem since the Samsung 950 pro can write at 940MB/sec).

SO... At this point, I'm very tempted to fault the storage controller, but it's so weird... Thinking about buying a PCIe storage card that would have both M.2 and SATA ports... Don't see any other option.

Anyone have a better idea?
 
Sustained writes will slow down as the cache fills up...

In short, do not expect advertised numbers at a constant basis on large writes...or lots of small reads.....

CHeck CrystalDiskMark sequential reads/writes to determine serviceability..
 
Sustained writes will slow down as the cache fills up...

In short, do not expect advertised numbers at a constant basis on large writes...or lots of small reads.....

CHeck CrystalDiskMark sequential reads/writes to determine serviceability..
 

ASK THE COMMUNITY

TRENDING THREADS