NVME Raid Speeds

[Nick980]

I have two Samsung PM981 1TB NVME drives in raid 0, below are the  results from CrystalDiskMark, do these look correct to you guys? Just RND4k looks low but not sure if that's normal or not

 

Run with standard setting

 

Run with NVME setting

[Windows7ge]

15 minutes ago, Benji said:

and among the reason why I think RAID with NVMe SSDs is useless

It also comes with various drawbacks such as what happened to Linus with his NVMe server.

[Dedayog]

20 minutes ago, Benji said:

Yes, they do look normal because sequential is the only sector that gains real advantages from RAID 0. After having looked at dozens of laptop tests with RAID 0 models, pretty much none has increased 4K rates. The results are perfectly fine and among the reason why I think RAID with NVMe SSDs is useless.

 

3 minutes ago, Windows7ge said:

It also comes with various drawbacks such as what happened to Linus with his NVMe server.

Correct me if I am wrong about this... I use 2x SATA SSDs in RAID, and I notice a 25-30% decrease in game load times, ones that take a substantial amount of time I should clarify (like Ark).

 

Now, my understanding is that NVMe and SATA have real world limitations of their on-paper speeds.  But... when accessing 2 drives at the same time, isn';t that completely separate and only limited by your CPU/Motherboard's ability to process the data streams?

 

Meaning if 1 is capped at anything... then 2 will be capped but since you're doing both at the same time you'll still see a boost to real world access speeds?

 

[Nick980]

2 hours ago, Benji said:

Yes, they do look normal because sequential is the only sector that gains real advantages from RAID 0. After having looked at dozens of laptop tests with RAID 0 models, pretty much none has increased 4K rates. The results are perfectly fine and among the reason why I think RAID with NVMe SSDs is useless.

Ok good to know, debating upgrading to X570 and grabbing a 980 Pro or WB Black drive and ditching the raid. Cant buy a GPU so might as well change some other parts

[Windows7ge]

1 hour ago, Dedayog said:

 

Correct me if I am wrong about this... I use 2x SATA SSDs in RAID, and I notice a 25-30% decrease in game load times, ones that take a substantial amount of time I should clarify (like Ark).

 

Now, my understanding is that NVMe and SATA have real world limitations of their on-paper speeds.  But... when accessing 2 drives at the same time, isn';t that completely separate and only limited by your CPU/Motherboard's ability to process the data streams?

 

Meaning if 1 is capped at anything... then 2 will be capped but since you're doing both at the same time you'll still see a boost to real world access speeds?

 

I'm afraid I don't understand the question.

 

Separate to Bandwidth or Throughput where there is a max theoretical speed you can reach IOPS are another factor and they determine how snappy & responsive accessing the storage feels.

 

IOPS isn't explicitly limited by the speed of the rest of the system where even if you cap the system bus for R/W speed IOPS can keep going up and that's what makes certain tasks feel really fast.

 

If that in any way answers your question.

[Dedayog]

13 minutes ago, Windows7ge said:

I'm afraid I don't understand the question.

 

Separate to Bandwidth or Throughput where there is a max theoretical speed you can reach IOPS are another factor and they determine how snappy & responsive accessing the storage feels.

 

IOPS isn't explicitly limited by the speed of the rest of the system where even if you cap the system bus for R/W speed IOPS can keep going up and that's what makes certain tasks feel really fast.

 

If that in any way answers your question.

If 1 car can only seat 4 people and only go 35 miles per hour on a road, regardless of how fast the car can actually move... then wouldn't 2 cars with 4 people at 35 miles per hour give you more people somewhere over a given time?

 

RAID 0 is two drives giving data at the same time vs just one normally.  How is that NOT faster and better?

 

RAID 0 is always better than 1 drive alone.  

 

That's my argument, for all my ignorance about RAID stuff.

[Windows7ge]

7 minutes ago, Dedayog said:

If 1 car can only seat 4 people and only go 35 miles per hour on a road, regardless of how fast the car can actually move... then wouldn't 2 cars with 4 people at 35 miles per hour give you more people somewhere over a given time?

 

RAID 0 is two drives giving data at the same time vs just one normally.  How is that NOT faster and better?

 

RAID 0 is always better than 1 drive alone.  

 

That's my argument, for all my ignorance about RAID stuff.

OK, so you're asking where is the disadvantage of RAID when it comes to speed.

 

That is a bit of a complicated question to answer because not all hardware combinations behave the same so where you may have no issues with one combination of hardware you could have several issues with another.

 

Going back to my example of Linus's NVMe RAID he had (IIRC) 24 NVMe SSD's RAIDed together. The problem is the system despite being an AMD EPYC 64 core couldn't keep up with the drives. They'd fetch the data the system requested but the system was so busy with the other drives that disks were timing out and resetting causing the whole storage array to drop to a crawl in performance.

 

Not only that but in a desktop unless you've got 40Gbit networking having a drive that can read/write well over 2000MB/s you really don't see the performance benefit of near doubling it with RAID except for when you're loading very large maps or data into system memory and even then it's a large expense for saving but a few seconds off load times.

 

Then there's the constant concern of potential data loss...it's just not worth it most of the time.