SSD Vs Fusion Drive iMac

[radmitry]

Low speed test after installing two sad

Can anyone help, please:

After installing two SSD on my 27' iMac I've tried Blackmagic disk speed test but it only shows 10 bmps or so. Simple copying of a 1 gb file from one folder to another also doesn't seem to be fast. I'v enabled TRIM but it hasn't changed anything...

Here's how I set it up step by step:

I've installed two SSD on my iMac (27-inch, Mid 2011, core i5)
At first I installed Crucial M500 240 Gb under DVD-Rom and was using it with my HDD as Fusion Drive.
Later I put Crucial MX100 512 Gb instead of HDD

I've set them up as RAID overall 750 gb or so.
Formatted and clean installed last Yosemite 10.10.2
Then I've discovered that my hard drive FAN is running at full speed - I've installed SSD Fan Control which is doing good - FAN is ok now.

I've also enabled trim via terminal as it shown here https://gist.github.com/return1/4058659/

When I'm checking SATA in system report it shows this

Intel 6 Series Chipset:

Vendor: Intel
Product: 6 Series Chipset
Link Speed: 6 Gigabit
Negotiated Link Speed: 6 Gigabit
Physical Interconnect: SATA
Description: AHCI Version 1.30 Supported


Capacity: 512,11 GB (512*110*190*592 bytes)
Model: Crucial_CT512MX100SSD1
Revision: MU01
Serial Number: 14440DA23C3B
Native Command Queuing: Yes
Queue Depth: 32
Removable Media: No
Detachable Drive: No
BSD Name: disk0
Medium Type: Solid State
TRIM Support: Yes
Partition Map Type: GPT (GUID Partition Table)
S.M.A.R.T. status: Verified

Crucial_CT240M500SSD1:

Capacity: 240,06 GB (240*057*409*536 bytes)
Model: Crucial_CT240M500SSD1
Revision: MU03
Serial Number: 1404096547D5
Native Command Queuing: Yes
Queue Depth: 32
Removable Media: No
Detachable Drive: No
BSD Name: disk1
Medium Type: Solid State
TRIM Support: Yes
Bay Name: SSD
Partition Map Type: GPT (GUID Partition Table)
S.M.A.R.T. status: Verified


So TRIM seems to be enabled.

But Blackmagic still shows something like 10-17 mbps for write


Speedtest at terminal shows

write speed

1024+0 records in
1024+0 records out
1073741824 bytes transferred in 69.301462 secs (15493783 bytes/sec)


read speed

1024+0 records in
1024+0 records out
1073741824 bytes transferred in 0.132797 secs (8085587788 bytes/sec)


Why writing speed is so small? I don't get it

 

[makkulai]

I asked the guys from the company that did the SSD Upgrade on my iMAc because I thought a SSD-RAID would be a performance Option for SSDs but the guys from macundpc.de told me actually it s not a good Idea as the single SSD-Option is the faster one. Plus , with RAID your Setup gets more likely to crach if you will have a problem with either SSD the whole RAID crashes. They configured the SSDs in my mac individually and it has a better PErformance - cheers from germany.

 

[Hughesy]

I am waiting for the rumoured iMac update this year.

What would you like to see as an update to the standard/affordable drive options?

 

[Dubadai]

I am waiting for the rumoured iMac update this year.

What would you like to see as an update to the standard/affordable drive options?

Standard Fusion/SSD on ALL Macs.

Also not charge people a fortune to upgrade SSD size...

 

[mtbdudex]

This thread helped me immensely understand the SDD vs Fusion drive points.
I'm looking at buying a new 27" 5k iMac.

 

[adgoodma]

I have gone with the 512 ssd. My computer is on a VESA mount and gets moved and tilted all of the time. I think that perhaps the movement isn't as good for the spinning disc of the fusion drive.

 

[ZachsMacDaddy]

I'm trying to decide between a 1TB fusion drive and a 256GB SSD when choosing between the refurbished 2014 iMac 27" 5K models. I've been spoiled for years by SSD speed, and recently setting up a HDD based 21.5" iMac for a family member was a reminder of how slow spinning disks really feel. I have a 960GB SSD in an external USB3 enclosure, so I could mount that behind the iMac and have plenty of direct connected space. I also have a 14TB NAS, so space really isn't a big issue overall. All of this seems to point me in the direction of the 256GB SSD internal with the external 960GB SSD.

 

[colodane]

Definitely go for the SSD, especially since you have experience with how fast they are and with using an external drive. No going backwards ;>)

 

[mtbdudex]

I ended up with the big 3TB fusion drive in my new 27" iMac , it's a non issue. I've had it 2weeks.
Start up takes 5-6 seconds, load and access of applications / files is near instantly.
I've got the machine with 24GB RAM and 4GB video card.

As I use the machine more it will balance what is stored in the 128GB SSD vs the 3TB HDD, in summary I'm satisfied and easily recommend others this.

For the record, I also own a 2013 MacBook Retina Pro with 256GB SSD, so far no difference in real world usage.

 

[maflynn]

Definitely go for the SSD, especially since you have experience with how fast they are and with using an external drive. No going backwards ;>)

I was worried about going backwards (so to speak), as I've gotten used to the speeds of the SSD in my MBP, but I also grew tired of needing external drives because the SSD size couldn't accommodate my data.

Its a double edge sword, get wicked fast speeds, but storage is suffering, get large drives, but performance can be impacted.

So far the 2TB fusion drive is allowing me to enjoy near SSD speeds and have all my data stored internally.

Would I rather have a 1TB SSD drive, sure, but the moneytree in the backyard suddenly died and I was unable to swing the cost

YMMV, but the Fusion drive isn't a horrible product and I'm happy with it

 

[Daisy81]

My problem with Apple's Fusion Drives is that they limit them to 128GB. I made a Fusion Drive for my 2012 Mac Mini with a Intel 250GB SSD. I almost never feel the slow down of the 5400RPM spinner.

That said when I bought my iMac I didn't feel like I could viably go in and make my own Fusion Drive because of the laminated screen. I don't want to risk my AppleCare warranty. This time I went with a 1TB SSD and a external 5TB drive from Costco. In this case I realize I spent a lot of money but I intend to keep this machine around for a while and I remember how slow my 15" MBP felt at the end because of the 5400RPM drive.

If Apple offered a 250 or 512GB SSD in the Fusion drive I would have been more willing to go for a fusion drive but 128GB is just too small in my opinion.

 

[maflynn]

If Apple offered a 250 or 512GB SSD in the Fusion drive I would have been more willing to go for a fusion drive but 128GB is just too small in my opinion.

That would be kind of cool, but I don't see much of an actual market that configuration.

Personally, I'd much rather have a SSD but my data occupies in excess of 500GB. I was tired of doing the external drive thing and wanted a more streamlined process.

 

[ggibson913]

I also recently purchased the Late 2015 iMac. I also struggled with this decision but I had to be honest, this computer is for personal use. It boots really fast and I have the space I need for all of my files. A few seconds here and there of waiting doesn't bother and the most intensive video editing I will do is 4k Shorts from my (future) iPhone.

 

[Daisy81]

I also recently purchased the Late 2015 iMac. I also struggled with this decision but I had to be honest, this computer is for personal use. It boots really fast and I have the space I need for all of my files. A few seconds here and there of waiting doesn't bother and the most intensive video editing I will do is 4k Shorts from my iPhone.

In the end everyone needs to make the decision for themselves. The fact that you struggled with the decision means you took the decision seriously. As a result I am sure that your iMac will serve you well.
[doublepost=1453221001][/doublepost]

That would be kind of cool, but I don't see much of an actual market that configuration.

Personally, I'd much rather have a SSD but my data occupies in excess of 500GB. I was tired of doing the external drive thing and wanted a more streamlined process.

How awesome would it be if Apple offered two PCIe SSD drives in their machines. I realize it would be expensive it would still be amazing. Once they remove the sata port I think they could do it easily enough.

 

[ddublu]

I just got my iMac 5k 27" and went with 2tb fusion, 32gb ram (self install), 4gb video and 4ghz i7 processor. I've noticed something pretty quickly. The fusion drive appears to function slower for Lightroom and Final Cut Pro for me than my late 2014 rMBP with a 512gb flash drive. I was actually quite shocked at the difference. Believe I am going to return it and go with the 1tb flash with same configuration otherwise.

 

[joema2]

I just got my iMac 5k 27" and went with 2tb fusion, 32gb ram (self install), 4gb video and 4ghz i7 processor. I've noticed something pretty quickly. The fusion drive appears to function slower for Lightroom and Final Cut Pro for me than my late 2014 rMBP with a 512gb flash drive. I was actually quite shocked at the difference. Believe I am going to return it and go with the 1tb flash with same configuration otherwise.

For a long time I had a 2013 top-spec iMac 27 with 3TB Fusion Drive and 2015 iMac 27 with 1TB SSD on my desk simultaneously, side by side. I did many tests with Lightroom and FCPX. In general I did not see a performance difference I would attribute to I/O. Some of the performance tests are in the attached spreadsheet. The I/O used during these was not recorded, but in general the I/O rate was not high enough where SSD vs Fusion Drive would make any difference. The differences are not due to I/O but CPU or GPU.

One of the most time consuming tasks in Lightroom is importing raw stills and creating 1:1 previews. If you observe the I/O rate it is quite low. That is a mostly CPU-bound operation.

Anybody can observe their I/O rate using Activity Monitor or iStat Menus. If the I/O rate is not over about 300-600MB/sec, then SSD won't make any difference in overall performance. The bottleneck is elsewhere.

 

[ddublu]

I know what you are saying but I also know what I have witnessed. Same exact workflow on a Wednesday and moved over to the iMac on a Thursday. The place I notice it the most is in Lightroom in the Develop module moving from image to image...an image starts somewhat blurry and then fills in with a sharper view. Importing images has been fine. I don't go spraying with a camera, pretty focused on aerial stuff so imports aren't massive...I just shoot a lot of actual projects so speed is important. I was at least expecting something faster than what I had moving to a much faster processor, more RAM and a better video processor.

 

[joema2]

The fusion drive appears to function slower for Lightroom and Final Cut Pro for me than my late 2014 rMBP with a 512gb flash drive....I know...what I have witnessed....in Lightroom in the Develop module moving from image to image...an image starts somewhat blurry and then fills in with a sharper view....

How do you know it's the Fusion Drive slowing it down? My 2015 iMac 27 with 1TB SSD is slower on some Lightroom tasks than my 2013 iMac 27 with 3TB Fusion Drive, but I don't claim the 1TB SSD is slowing it down.

Do your above task, then in Lightroom>Preferences>Performance turn off the GPU and immediately do the same thing. See if that makes any difference. On my 2015 iMac 27 it's considerably faster with the GPU off, which is a problem with Adobe's software.

 

[varian55zx]

I bought my first fusion drive in december with my iMac

I have experienced SSD speeds nearly the whole time, the only time I have not is when opening an app that isn't on the SSD portion. However, on the next time of opening that app, since it is now on the ssd portion, I experience SSD speeds.

Sorry, but don't know what all the complaining is about. I mainly see it from people who don't have one.

 

[imac09]

I was worried about going backwards (so to speak), as I've gotten used to the speeds of the SSD in my MBP, but I also grew tired of needing external drives because the SSD size couldn't accommodate my data.

Its a double edge sword, get wicked fast speeds, but storage is suffering, get large drives, but performance can be impacted.

So far the 2TB fusion drive is allowing me to enjoy near SSD speeds and have all my data stored internally.

Would I rather have a 1TB SSD drive, sure, but the moneytree in the backyard suddenly died and I was unable to swing the cost

YMMV, but the Fusion drive isn't a horrible product and I'm happy with it

I just unjoined my 2TB Fusion Drive. Installed El Capitan on the 128GB SSD and will install all my media files to the 2TB 7200 RPM Seagate. We'll see how it works out

 

[varian55zx]

I just unjoined my 2TB Fusion Drive. Installed El Capitan on the 128GB SSD and will install all my media files to the 2TB 7200 RPM Seagate.

I'm not knocking the decision, just wondering why.

If fusion technology can theoretically move the files more efficiently than a user would ever hope to, why do it yourself?

 

[imac09]

I'm not knocking the decision, just wondering why.

If fusion technology can theoretically move the files more efficiently than a user would ever hope to, why do it yourself?

Just wanted to see if I could tell a difference...

 

[maflynn]

I just unjoined my 2TB Fusion Drive. Installed El Capitan on the 128GB SSD and will install all my media files to the 2TB 7200 RPM Seagate. We'll see how it works out

I was kicking around that idea so I could install Windows on the SSD, instead of being forced to run it on the spinning disk, but I think 64GB for the OS may be too small in the long run and so I'd not have the best of both worlds but the worst.

 

[varian55zx]

Just wanted to see if I could tell a difference...

Well, let me tell you

That is a very good reason. And you also know you can re-merge the two at any point, should you want to.

It's an interesting experiment. I don't know. Because of what I have continuously heard about fusion, the option seemed to me, not appropriate.

However. Should it be justified as the superior choice, I have absolutely no opposition to attempting it myself.

Good luck.

 

[Fishrrman]

varian wrote above:
"If fusion technology can theoretically move the files more efficiently than a user would ever hope to, why do it yourself?"

I disagree, kind of...

imac09 wrote above that he just "DE-fused" a 2tb fusion drive -- which would split it into a 128gb SSD + 2tb 7200rpm HDD.

The result yields an SSD that will now -always- operate at "SSD speeds", leaving the "file-shuffling" to the user, not to the OS.

The "trick" here is to properly manage both drives as to "what goes where".
If one keeps the SSD "lean and clean", it won't slow down, even as the iMac ages.

I would install onto the SSD:
- the OS
- applications
- my user account (with modification)

By "modification", I -WOULD NOT- keep libraries on it containing photos, music, movies or other huge chunks of data files.
Those would be stored on the HDD.

Properly setup, one could keep 35-50% of the SSD "free" for swap files, temp files, etc.
And leave "the seldom-accessed stuff" on the HDD.