Two partitions: the same disk vs separate disks

[giotmua28]

Is it faster to open files on the D partition if I have the C and D partitions on the same SSD, or on separate SSDs? Providing that those SSDs are of the same brand, model and speed.

 

[ElectrO_90]

Seperate will be faster, by how much I don't know.

 

[4745454b]

There shouldn't be any difference.

HDDs are a spinning disk. Like a record. At the outer edge of the disk the speeds are faster. Meaning if you had a C and D partition on a HDD the C would have faster transfer speeds compared to D. But a SSD is just like RAM. There is no faster or slower parts of it. It's just ram. Or in this case the SSD. I wouldn't bother setting up partitions on an SSD.

 

[ElectrO_90]

I thought about this and what you said, but if the computer is doing something on C drive and saturating the Sata, trying to do something on D drive would slow it down, which is why I came to the conclusion that seperate is faster, but I really don't think it will be a lot faster.
As you said, a spinning HDD is different which would have more of an impact.
But I have copied from 2 SSDs before while the computer was doing something, and the main drive was being utilised while I was copying which gave the performance hit. I'd guess it was the C drive using the Sata, and then trying to use more Sata bandwidth to copy.

Maybe I am just wrong, but that's what I thought was happening.

There shouldn't be any difference.

HDDs are a spinning disk. Like a record. At the outer edge of the disk the speeds are faster. Meaning if you had a C and D partition on a HDD the C would have faster transfer speeds compared to D. But a SSD is just like RAM. There is no faster or slower parts of it. It's just ram. Or in this case the SSD. I wouldn't bother setting up partitions on an SSD.

 

[das_stig]

SATA3 top end is about 600MB/s, so if SSD1 hits 550MB/s SSD2 can only hit 50MB/s, all the ports on your motherboard share the SATA3 link.

Using multiple drives becomes viable, when you know nothing will satuate the link, which mechanical HDD's cannot do, but SSDs can almost do.

If you look at my rig, you will see I use an NVMe for Windows and apps, while the MX500 is used for steam,origin and game installs, while the third cheapo SSD is used for swapfile, temp folders and windows updates, as I know it will never satuate the SATA3 link, so ensuring the MX500 gets as much link speed as it can handle.

 

[ElectrO_90]

SATA3 top end is about 600MB/s, so if SSD1 hits 550MB/s SSD2 can only hit 50MB/s, all the ports on your motherboard share the SATA3 link.

Using multiple drives becomes viable, when you know nothing will satuate the link, which mechanical HDD's cannot do, but SSDs can almost do.

If you look at my rig, you will see I use an NVMe for Windows and apps, while the MX500 is used for steam,origin and game installs, while the third cheapo SSD is used for swapfile, temp folders and windows updates, as I know it will never satuate the SATA3 link, so ensuring the MX500 gets as much link speed as it can handle.

With overheads we know you can never get 600MB, but I am surprised you still use a swapfile, since you have 16GB Ram. I disabled my swap file and everything still runs as good without it.

 

[4745454b]

I hadn't thought of the SATA bus. That's probably very chipset dependent. But SATA is a serial point to point connection. What happens to SATA0 shouldn't impact SATA2. Using a third party chipset can change things, but I would think you should see full speed on both. I don't have two SATA III drives to test this however.

 

[USAFRet]

Is it faster to open files on the D partition if I have the C and D partitions on the same SSD, or on separate SSDs? Providing that those SSDs are of the same brand, model and speed.

On an SSD, partitions do not matter. That is simply a logical display, show to you the user.
The drive puts the bits wherever it feels like.

Unlike a spinning HDD, where the partitions are a physical location, and the actual rotational speed makes a difference.


Copying within the same drive or between two drives makes a difference.
Here, this is between the same source 850 EVO, and either the same 850 target or an 860 EVO target.
Approx 8GB files, freshly copied to this source drive.

But we also see it matters how fast the drive can actually sustain that write speed.
They both start out at the magic uber number of around 500 that we always see advertised.

Copying within the same drive (again, "partitions" do not matter) is slower than copying to another physical drive.
I'd expect an 850 PRO would sustain that top speed longer than the EVO.

For your question about "opening a file"? Can you tell the difference between 0.02 sec and 0.04 sec?
Good quality SSD's have near zero access time, no matter if on the same drive or a different drive.

 

[das_stig]

Even with 16GB, have found a small swapfile does help performance with the data I use, probably just Windows rubbish being paged out.