Drawbacks to external SSD?

[infernoguy]

Bought an iMac 4k (base model with 1TB HDD) last Saturday and I love the display but the 1TB HDD sucks. I thought that I could live with it but its just too slow.

Yesterday, I bought an external USB3 SSD drive (on sale at Best Buy, 480GB for $159), used Super Duper to clone the drive and set the External USB as the boot drive and boom! much much better speed. I debated getting a Thunderbolt drive instead of USB3 (I still might) but for right now, the speed is good.

Any drawbacks to working this way permanently? Any technical issues that I may be missing?

Since I'm still a week into my return period, I could just return this iMac and preorder a 256GB SSD but the seemed like a cheaper solution.

Thanks!

 

[cynics]

Potential for random unmounts. And not as fast as internal solutions.

Many people do it, if you can't bare the speed and don't want to replace the internal drive then its your best solution.

Personally I would return it. You basically have a brand new machine that you arent happy with. And an external SSD is a band aid to your problem. Plus I think you'll be happier with the speeds of the internal PCIe based SSD.

 

[Weaselboy]

Any drawbacks to working this way permanently? Any technical issues that I may be missing?

It will be much slower than an internal flash storage device. Also, TRIM does not work with macOS over USB. May or may not be an issue for you. Some people run without TRIM and never have slowdowns, others without TRIM experience a reduction in write speeds over time.

If this were a couple years old iMac and you wanted to do this as an upgrade, I'd say great. But I'm kinda with @cynics here hating to see a brand new machine running with a work around like this.

 

[Fishrrman]

Frankly, a new iMac with (at least) the 2tb fusion option would be considerably faster, but...
...you'll still do fine by booting and running from the USB3 SSD.

There's no real advantage to booting from thunderbolt, vis-a-vis booting from USB3.
The speeds will be the same. In some cases thunderbolt is slower, not faster.

Thunderbolt -does- allow TRIM to be used (not usable via USB3), but for all practical purposes, TRIM is over-rated and of no real consequence with a USB3 "external booter".

I've been booting and running a late-2012 Mac Mini using a USB3 SSD for over FOUR YEARS now, and it boots and runs as well as the first day. TRIM has never been needed.

Some folks use a piece of velcro to attach the external USB3 SSD to the back of the iMac's stand -- out of sight and out of the way...

 

[mccltd]

I have a new Mac as well and always go for the fusion drive. I also repair and upgrade them and the standard mechanicals are just to slow so the best compromise for speed and space is the 2tb fusion. I would take it back and upgrade while u can. Also take out the 3yr warranty but buy that on eBay around £80

 

[infernoguy]

Frankly, a new iMac with (at least) the 2tb fusion option would be considerably faster, but...
...you'll still do fine by booting and running from the USB3 SSD.

There's no real advantage to booting from thunderbolt, vis-a-vis booting from USB3.
The speeds will be the same. In some cases thunderbolt is slower, not faster.

Thunderbolt -does- allow TRIM to be used (not usable via USB3), but for all practical purposes, TRIM is over-rated and of no real consequence with a USB3 "external booter".

I've been booting and running a late-2012 Mac Mini using a USB3 SSD for over FOUR YEARS now, and it boots and runs as well as the first day. TRIM has never been needed.

Some folks use a piece of velcro to attach the external USB3 SSD to the back of the iMac's stand -- out of sight and out of the way...

So you've noticed no speed increase with a Thunderbolt SSD Drive? I just ordered one from Amazon so I guess I'll see for myself but I'm assuming you tried this already.
[doublepost=1488726974][/doublepost]

I have a new Mac as well and always go for the fusion drive. I also repair and upgrade them and the standard mechanicals are just to slow so the best compromise for speed and space is the 2tb fusion. I would take it back and upgrade while u can. Also take out the 3yr warranty but buy that on eBay around £80

Thanks for the suggestion but you're talking an almost $1000 price difference (if I got the 27 inch). $500 (with tax) if I upgraded the 4k to the 2TB Fusion. The external SSD seems like an inexpensive option that lets me keep the internal drive for storage.

 

[cynics]

Ahem....

Good job Apple... (slow clap).

 

[infernoguy]

Potential for random unmounts. And not as fast as internal solutions.

Many people do it, if you can't bare the speed and don't want to replace the internal drive then its your best solution.

Personally I would return it. You basically have a brand new machine that you arent happy with. And an external SSD is a band aid to your problem. Plus I think you'll be happier with the speeds of the internal PCIe based SSD.

That's the problem. I don't want to void the warranty and replace the drive myself. I can do it (IT Tech for 20 plus years) but if there is any kind of breakdown that requires a trip to the Apple Store, I'd be SOL.

Maybe I could exchange it for a BTO with a 256GB SSD. Hmmmm....
[doublepost=1488727314][/doublepost]

Ahem....

View attachment 691053

Good job Apple... (slow clap).

I understand why they did it (more storage bang for the buck plus keeps prices somewhat lower) but after having MacBooks with SSD drives for years this slowdown was just unbearable. How did we survive with platter drives for so long?

 

[Weaselboy]

So you've noticed no speed increase with a Thunderbolt SSD Drive? I just ordered one from Amazon so I guess I'll see for myself but I'm assuming you tried this already.

See this test. You won't likely see any in speed difference. But TB does get you TRIM like I mentioned.

 

[merkinmuffley]

return it and get the machine you want/need. those itb drives are not a good idea.

 

[mccltd]

Didn't the model you've bought have no fusion option? As any fusions better than non then just added extra storage via USB or nas

 

[cynics]

I understand why they did it (more storage bang for the buck plus keeps prices somewhat lower) but after having MacBooks with SSD drives for years this slowdown was just unbearable. How did we survive with platter drives for so long?

Not so sure, we are talking pennies on the dollar. 1tb HDD 5400 and 7200rpm have met or are nearing the point where they can't be made any cheaper due to the literal cost of the components unrelated to storage. Meaning its can be just as cheap to make 512gb as 1tb.

If we take a look on Amazon I find this (your iMac uses a 2.5" drive)

Toshiba 5400 RPM 1TB 2.5" = 54.25 (on sale)

https://www.amazon.com/Toshiba-5400...d=1488729082&sr=8-2&keywords=5400+rpm+1tb+2.5

WD 7200 RPM 1TB 2.5" = 69.99 (not on sale)

https://www.amazon.com/Black-Perfor...29496&sr=8-2&keywords=7200+rpm+2.5+hard+drive

If you are going to use a HDD at least use a 7200 RPM drive. The performance is WELL worth that 15 bucks, less depending on sales.

I'm still using 7200 HDD on my current iMac. And its bearable but not by much. Next iMac will likely have a 3tb Fusion, maybe a 2tb SSD if I hit the lottery.

 

[infernoguy]

Didn't the model you've bought have no fusion option? As any fusions better than non then just added extra storage via USB or nas

It does but if I go that route I might as well order an internal SSD drive which Apple charges me an extra $200 for 256GB.

The external 480GB SSD USB3 drive only costed me $159 at Best Buy.

 

[cynics]

See this test. You won't likely see any in speed difference. But TB does get you TRIM like I mentioned.

I don't have a strong grasp on TRIM but its prominently featured in Apples upcoming APFS. Do you think it will be supported via USB connected drives?

 

[infernoguy]

I don't have a strong grasp on TRIM but its prominently featured in Apples upcoming APFS. Do you think it will be supported via USB connected drives?

Good question. I know it's supported on Thunderbolt 2 (and 3) via the OS so I'm pretty sure it will be in the future.

 

[cynics]

It does but if I go that route I might as well order an internal SSD drive which Apple charges me an extra $200 for 256GB.

The external 480GB SSD USB3 drive only costed me $159 at Best Buy.

Apple uses a PCIe based SSD. Its performance will far exceed your external, it would far exceed your external even if you connected it internally. Similar SSD's @ 256gb on Amazon are around 130 dollars. So 200 for it installed and warrantied isn't too unreasonable.

EDIT: I should note it will far exceed your SSD in performance in certain situation. Many people still stand by SATA3 SSD's for reasonable reasons, cost vs storage vs performance mostly.

 

[btdpi007]

I'm no expert, but I went this route (i.e. added a external SSD over USB3) with a 2012 Mac Mini and the difference in speed was night and day for the better. I'm guessing I may have been able to get more speed had I gone internal but it worked well for me. Also, never one issue relating to boot errors due to mounting issues. It was a good option for me. Obviously, you have a new machine you spent a lot on, so do what you feel is best, but this is a good option if it's how you decide to proceed.

 

[Weaselboy]

I don't have a strong grasp on TRIM but its prominently featured in Apples upcoming APFS. Do you think it will be supported via USB connected drives?

I have not seen anything either way. The TRIM ATA command cannot be passed over USB. What can be done is on UASP supported USB enclosures the SCSI UNMAP command (like TRIM) can be passed along. Windows can now do that and macOS cannot. So Apple could add that SCSI command to macOS and give you the equivalent of TRIM on a USB drive if they wanted. Given what an edge case this is, I'm guessing it will not happen.

 

[cynics]

I have not seen anything either way. The TRIM ATA command cannot be passed over USB. What can be done is on UASP supported USB enclosures the SCSI UNMAP command (like TRIM) can be passed along. Windows can now do that and macOS cannot. So Apple could add that SCSI command to macOS and give you the equivalent of TRIM on a USB drive if they wanted. Given what an edge case this is, I'm guessing it will not happen.

Thanks for the info.

I also find it unlikely but its good to know its possible.

I wonder if their reasoning to implement this will be swayed slightly by using all USB C ports. Basically making an effort to make their (Apples) USB C as fully functional as possible since it seems they are pushing this USB C charge. I know it seems like a moot point since its possible now, but APFS details seem to highlight TRIM and Apple seems to want to use only USB C moving forward.... I'm probably making connections that don't exist...

 

[Fancuku]

I would return it and get one with the 256gb ssd.

 

[D.T.]

Yeah, no question, I'd return it while you have the option (assuming you're on your 8th day of ownership), get one with flash storage OOTB. If you need extra storage, _then_ I'd consider something external, but not as my primary drive (1-2TB HDD for archive, low performance needs).

 

[cynics]

@Weaselboy Researching further into APFS how necessary do you think TRIM will even be? Seems like with its optimization of how it writes data for SSD's it might be even less necessary then it is now (which you say already isn't much).

Seems like a tough question to even ask the APFS beta testers since you would need to measure a degradation of performance over time. Not just ask if TRIM works or not.
[doublepost=1488733408][/doublepost]OP: Make sure to get the 256gb SSD or if you go for the Fusion get the 2tb or bigger. They come with larger SSD sections then the 1tb model, more bang for your buck. I believe 1tb fusion comes with 24gb SSD section and 2tb comes with 124gb section (I could be wrong about the exact numbers but its similar).

 

[Weaselboy]

Researching further into APFS how necessary do you think TRIM will even be? Seems like with its optimization of how it writes data for SSD's it might be even less necessary then it is now (which you say already isn't much).

Just the small amount of reading I have done on APFS so far, I don' feel qualified to weigh in on that. Sorry

 

[colinsky]

The internal SSDs are significantly faster. My late 2015 5K boots in 22 seconds from the internal 256GB SSD, and 59 seconds from an external 1GB SSD via USB3.

 

[infernoguy]

The internal SSDs are significantly faster. My late 2015 5K boots in 22 seconds from the internal 256GB SSD, and 59 seconds from an external 1GB SSD via USB3.

...but both boot faster than the internal 5400rpm drive!