iMac Late 2015 1TB Fusion vs 2TB Fusion

ivantwilliams

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Original poster
Nov 30, 2014
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Atlanta, GA
Screen Shot 2016-06-01 at 2.53.53 PM.png

I'd like it to be known, I stand corrected!
There is a MAJOR difference between the iMac Late 2015 1TB Fusion, versus the 2TB Fusion.

A few hours ago, I upgraded from the 1TB Fusion model, to the 2TB Fusion (I wished I could have bought the 1TB SSD!) and there is a clear difference.

When running the Blackmagic speed test, I was getting read speeds of 570MB/s to 650MB/s and write speeds of 1488MB/s to 1500MB/s, oh, and this was while I was coping data to the drive. Test still running...
 

ivantwilliams

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Original poster
Nov 30, 2014
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Atlanta, GA
Seriously, I was in denial. I conversed with many people on the forums about this. But, after testing BOTH myself, I can clearly see a major difference. I can only image how much faster it would be with a pure SSD (PCIe). I just can't afford one with a pure SSD at the moment...

So, the 2TB is that much superior??
 
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RedlegsFan

macrumors 6502
Mar 15, 2012
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Yeah but that is plenty fast... well I guess that is subjective. It would be plenty fast for what I do. That's good to know!
 
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TheBro72

macrumors member
Apr 21, 2016
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2
Manchester, UK
View attachment 633910

I'd like it to be known, I stand corrected!
There is a MAJOR difference between the iMac Late 2015 1TB Fusion, versus the 2TB Fusion.

A few hours ago, I upgraded from the 1TB Fusion model, to the 2TB Fusion (I wished I could have bought the 1TB SSD!) and there is a clear difference.

When running the Blackmagic speed test, I was getting read speeds of 570MB/s to 650MB/s and write speeds of 1488MB/s to 1500MB/s, oh, and this was while I was coping data to the drive. Test still running...
Blackmagic speed test with a 1TB SSD..........
 

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varian55zx

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May 10, 2012
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It's even faster than that.

The read speeds of the 128 gb SSD can reach 1800 mb/s, which is the same speed as the 256 gb SSD.

For someone like me who split their fusion, I guess now I have an SSD as fast as the 256 SSD and another 2tb of internal storage for media and file storage.
 
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maflynn

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May 3, 2009
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I'd like it to be known, I stand corrected!
There is a MAJOR difference between the iMac Late 2015 1TB Fusion, versus the 2TB Fusion.
So what is the major difference, I'm confused.

I only see a single Blackmagic test, is that the 1TB drive, or the 2TB drive?
What's the read/write speeds of the 1TB drive and lets compare that with the 2TB drive.

I'm not saying the 1TB is as fast, but rather, I don't see the comparison and details in your post, unless I missed it
 
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ivantwilliams

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Original poster
Nov 30, 2014
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Atlanta, GA
Sorry, you're right. I merely posted the 2TB Fusion drive stats. I no longer have the 1TB one to post the stats. I was more doing this from memory. When I had the 1TB, last week, the stats were no where as good as the 2TB stats I posted in my initial post.

Yes, a side-by-side would have been better to post.

So what is the major difference, I'm confused.

I only see a single Blackmagic test, is that the 1TB drive, or the 2TB drive?
What's the read/write speeds of the 1TB drive and lets compare that with the 2TB drive.

I'm not saying the 1TB is as fast, but rather, I don't see the comparison and details in your post, unless I missed it
 
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sartrekid

macrumors 6502a
Oct 30, 2014
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Germany
It's even faster than that.

The read speeds of the 128 gb SSD can reach 1800 mb/s, which is the same speed as the 256 gb SSD.

For someone like me who split their fusion, I guess now I have an SSD as fast as the 256 SSD and another 2tb of internal storage for media and file storage.
I read your other thread and like your solution of splitting up the two drives. When I first installed Bootcamp and wanted to delete it again, it messed up the Fusion drive, so I had to recreate the Fusion drive manually. It was then when I contemplated whether it'd not be a good idea to just have them separated as you have.

As for the topic, my READ speeds are just below 1800 MB/s and my WRITE speeds approx. at 665 MB/s. Like the OP, I have a 2TB Fusion drive (late 2015 model).
 
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varian55zx

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May 10, 2012
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San Francisco
I read your other thread and like your solution of splitting up the two drives. When I first installed Bootcamp and wanted to delete it again, it messed up the Fusion drive, so I had to recreate the Fusion drive manually. It was then when I contemplated whether it'd not be a good idea to just have them separated as you have.
I can tell you that at least for me, it is so much better.

In my case the Fusion technology actually won't organize the files better than I can, because it will forcibly move files onto the SSD that don't need to be there. Once SSDs are more than 75% full, their speed starts to decline, so I see that as somewhat of a flaw in the technology.

With my Applications Folder, Library, System, and users folder on the SSD, I have over 60gb free. But I never want/need anything more to go on the SSD.

Unfusing them allows a level of micromanagement that is highly satisfying.

Likewise my internal spinner has about 800gb of essentially media files that wouldn't even benefit from being on an SSD.

I'd recommend to anyone who is intrigued by the idea to at least try it, it's a no risk project that can be reversed in a matter of minutes.
 
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imacken

macrumors 65816
Feb 28, 2010
1,232
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Can someone explain Blackmagic to me? When I run it on my 2Tb fusion, the read write speeds go up and down dramatically as do the results on the right hand side. There is never a 'final figure'.
I can't make any sense of what I see!
Example attached
 

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rbart

macrumors 6502a
Nov 3, 2013
513
229
France
It's due to the fusion drive technology.
When you fill up the ssd portion, you use the hdd and get slower performance.
Black magic is not the perfect benchmark for fusion drives.
On empty FD, you will get very fast scores.
But when you have more than 128gb, blackmagic will give inconsistent results
 
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imacken

macrumors 65816
Feb 28, 2010
1,232
123
It's due to the fusion drive technology.
When you fill up the ssd portion, you use the hdd and get slower performance.
Black magic is not the perfect benchmark for fusion drives.
On empty FD, you will get very fast scores.
But when you have more than 128gb, blackmagic will give inconsistent results
Funnily enough, I ran it again later, and it was giving very consistent results, so I remain confused!
 

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aesc80

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Mar 24, 2015
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I'd murder just for the Fusion Drive itself. Damn disk hard drives. BTW, OP, where did you get the upgrade done at?
 
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