This speed is impossible, isn't it?

Pejole2165 · 03 Sep 2019

My system is Intel 660p PCIE x4 NVME boot disk (works at full speed, 1600Mb/s reads, 960-1000Mb/s writes)
A SanDisk 3D Ultra SATA 3 SSD and a 1Tb Seagate Barracuda SATA 3 7200Rpm HDD.
My boot drive contains 21Gb of files (Windows and a few utility apps).
If I run a full imaging of this drive with Macrium Free with medium compression and use the 1Tb HDD as the destination, the process takes 2.41 minutes including verifying the image.
This I think works out to near as damn it 790Mb/s written, this seems right from what I've read about the SATA 3 interface being a theoretical 6Gb/s but with overheads tends to cap out at 550Mb/s or there about.
I have turned off Windows write caching for all drives.
So what do these numbers really represent, see picture?

This speed is impossible, isn't it?-macriumdesk01.png

Because I really doubt a mechanical HDD can actually write at 30ish Gb/s.

bro67 · 04 Sep 2019

That info should be sent to Macirum.

Pejole2165 · 07 Sep 2019

Does anyone else have the same remarkable speeds reported? This is a fresh windows install, fully updated and a new install of Macrium, fully updated.
The images I create do work when restored so the speed isn't affecting the functionality of Macrium, I was just wondering how it works out that speed for writes, the read would probably be about right I think for an SSD.

dalchina · 07 Sep 2019

Hi, there have been other discussions on this e.g.
Strange Write Speed in Macrium Reflect Free

Pejole2165 · 07 Sep 2019

Hmm, ok, read that post, still none the wiser, Macrium must be using an odd calculation to come up with that write speed. I will have to wade through Macrium forums if I can access them.
But thankyou for the link.

- - - Updated - - -

Ok, seems Macrium uses a RAM cache before writing to disk and that reported write speed is for that cache, not actual disk write speed but memory write speed. At least that's what I get from Macrium's forums.

jimbo45 · 07 Sep 2019

Hi folks

@Pejole2165

the easy way to test and verify disk speed is to boot up a live linux system and use the venerable dd command with following parameters

dd if=/dev/sdx1 of=/dev/sdx2 bs=16M status=progress where sdx1 and sdx2 are 2 disks (use lsblk command to show disks)

This program does raw read / writes -- doesn't matter what the file systems are - it simply just read and writes blocks of data. The status=progress command shows you the read/write rate -- let it run say for around 3 -4 mins when the rate is stable -- you don't have to copy a whole disk but it shows your actual I/O rate , bytes copied and time elapsed-- I have proposed this solution as I can't think of anything else that just reads/writes data without caring about the underlying file system /structure.

The I/O rate is accurate -- you can check that easily enough with the bytes read/written against the elapsed time. I think on a USB3 connection on a laptop two SSD's ( really cheap kingston ones connected by sata-->usb3 connectors) I was getting about 300MB/s

This speed is impossible, isn't it?-screenshot_20190907_100133.png

just boot up any live linux via a usb so nothing touches your windows OS disk (don't do the dd command using your os disk as the output file of course).

If there's an equivalent Windows command to the dd command - please post it - would be quite useful in some cases for simply copying partitions etc (dd copies those too as well as whole disks independent of any file system).

Granted you were using faster HDD's / SSD's internally not via a USB3+sata adapter your speeds look about right for the mobo bus and quality of Disks you have..

cheers
jimbo

Compumind · 07 Sep 2019

I will add just one thing...

Macrium, when used with an SSD boot drive and backing up to another SSD is tremendously fast!
Be sure to check off the "verification" after writing to ensure that the checksums match completely.

Macrium blows Acronis out of the water...

FWIW

topgundcp · 08 Sep 2019

By default, Macrium report transfer rates is in Mega bits/second (Mb/s). Divide by 8 will report in bytes (MB/s)