My brand new iMac "Late 2015" is SO SLOW. Why?

I too have just bought a new late 2015 iMac last week as an upgrade to a 2010 MacBook pro only to be feeling disappointed as i hadn't seen beach balls for years and felt like I had downgraded.

After spending a week talking tp AppleCare and trying allsorts I couldn't see any resource hog so I have today cloned my HDD to a USB3 external SSD and booted from the SSD as the startup disk the iMac is now lightning fast, like really really fast. iTunes launches with no bounce!

I have concluded the bottle neck was the internal iMac hard drive which seems to have slowed everything down.

I ended up with a 250gb Samsung T3 which is now the OS and the original internal is disk used for storage.

Not ideal when you have just dropped £1000 on a new iMac but it seems to have fixed mine.

Get an external SSD in a USB 3.0 or Thunderbolt enclosure format the SSD for Mac use using OS X Disk Utility App and then clone your current system to the external SSD using Bombich's CarbonCopyClone or Shirt Pocket's SuperDuper clonning apps and run your 2015, 21 inch screen exclusively from this newly purchased externally enclosed SSD.

This is the only way to make these newer slimline, 21 inch screen iMacs faster.

Good Luck!

FYI, all 21" iMacs now come with the default 5400 rpm hard drives (unless you order an SSD) and they are about 30+% slower than the 7200 rpm drives in 27" iMacs. Personally, I can't stand the slowness of them; when I got my Macbook Pro with one, I immediately upgraded the hard drive.

Do you not find there is a CPU hit running the drive through USB 3.0 as it's not a native storage bus like say using the Thunderbolt ports. TB external chassis are expensive though!!! My late 2015 is totally unusable so I'll have to try this. Can you boot of of a USB 3 Stick at a reasonable rate or is SSD the only way?

Thanks all for sharing your experiences!

You still can opt for an SSD in a USB 3.0 enclosure.

Even with an SSD in a USB 3.0 enclosure, the 21 inch screen iMac you have will be A LOT faster than the internal bus driven 5400 spinning mechanical hard drive.

Your throughput, either through USB 3.0 or Thunderbolt should be near instantaneous response using an external SSD.

I opted for one of these and will be trying to do the clone this weekend - thank you.

http://amzn.to/2nmWujs

Question though, how can I (after imaging) switch around my user accounts so that the home folders remain on the slower integrated hard drive but the operating system and apps work from the newly imaged SSD?

Can I wipe the internal drive and then relocate the user folders back to the hard drive without screwing up permissions and settings?

Thanks for any enlightenment you can offer!

The only other thing I could find is your BackBlaze backup software.

Makr sure that this is setup to perform backups only when you are away from your Mac for prolonged periods of time and it is NOT trying to perform backups while you are actually using your Mac.

You only have 8 GBs of RAM installed so, I am NOT sure if just the external SSD is going to help your situation.

OS X and macOS Sierra need a full 8 GBs of RAM for nominal operation, now.

The physical RAM in the newer Macs has that integrated Intel GPU that gets all of it needed VRAM from the total amount of install physical RAM.

It is, probably, NOT helping the RAM and borrowed RAM for the GPU when you are running your Cintiq tablet which requires even more GPU VRAM that is borrowed from the physically installed RAM.

So, your available 8 GBs of RAM is NOT going very far to use with running applications, the iMac's own screen graphics and the Cintiq tablet!

The integrated GPU is pulling physical RAM for VRAM to drive graphics on two screens instead of just one.

My advice?

Sell that iMac!

If you absolutely need to stay with the less expensive 21 inch screen model iMacs, get the top of the line iMac with ALL the optional i7 CPU model, 16 GBs of RAM and the 512 GBs (NOT the 256 GBs) internal SSD.

That top of line 21 inch screen iMac model should give you enough power and performance and ensure some futureproofing for quite some time!

😉

If you can swing it finamcially, look at and consider a mid range 27 inch screen iMac with a mid range CPU, better, faster discreet, independent GPU, and an SSD ONLY option.

The 27 inch models can have cheaper user installable RAM and the 27 inch screen models can take UP TO 32 GBs of install RAM.

Good Luck to You!

Well I went ahead and bought the Samsung External SSD - this one - a 500 Gb http://amzn.to/2mfyEpA.

I used the Carbon Copy Cloner which works as a full application even in trial mode and did a clone of my system disk to the SSD (after formatting it for Mac format, GUID) I then tested a boot holding down the Option key on bootup and selecting the SSD - it booted so darn fast! Apps were loading like a real i5 computer should work!!! I changed my startup drive in System Preferences and then changed all of the user home folders to point BACK to the internal hard drive (as document storage for the family was HUGE!! and speed is not an issue for iTunes, etc)

Now the computer works like it should have done in the first place. Sad to have to have invested more money in the machine but I guess it was too good to be true getting a cheap (thinking quality Mac) in the first place. The 5400rpm drive cripples what is otherwise a reasonable spec'd machine. No more impulse buys for me again LOL, I need a machine I can rip open and swap out drives and memory - lesson learned and now useless machine revived to live a while longer.

Thanks to the person advising the external SSD, I did not think the performance hike would be enough but it is amazing!!

One of the major problems with any newer 21" is the fact that they use a slow 5400 rpm drive, which is more than 30% slower than the standard 7200 rpm drive in a 27" iMac. I've had two and sold the Mini within 2 months (at a loss) because I couldn't stand its slowness and the second in an MBP which I replaced with an SSD immediately. My personal opinion: I really do not understand how anyone can sell a computer with such a basic, barely minimal hard drive for more than $400 or so since the read/write speed is what determines how fast or slow your drive responds/does what you tell it to do.

Well, I've got a 27" mid-2011 iMac. What's my problem? Well, having recently upgraded to Sierra, it was sooooo slow you could have a shower while you wait on say Photos to open.

The guys here on Community told me to run a diagnostic test, then they could see that the original RAM that was supposed to come with my iMac was removed and swapped with RAM from an 09 model, which is like putting a car battery from a 1 litre engine into a car with a 2 litre engine, it's got no oomph. Having contacted the shop where we bought it, who seemed to be totally flabbergasted that it happened, we are now waiting over a month for them to replace it.........

If you go into the Apple icon on top left, click "About this Mac" copy that "Memory" bit and these guys will know if it's the right one for your machine or not.

It's a start - hope it helps!

How Apple could have used such archaic parts is beyond me. 7200rpm drives had been the standard even in laptops far before the 2015 iMacs came out. Very poor choice. I'm just glad the SSD mod has outperformed my expectations and saved a doorstop iMac!!!

It is the awfully under-spec'd hard drive that is letting you down - it is a HUGE bottleneck. I bought one of these after a recommendation http://amzn.to/2mfyEpA and cloned my system drive then made the SSD the boot drive. I described it more above and how to relocate your home folders back to the 1Tb drive as speed is a lesser issue for data files vs program and system files. This made the system responsive and usable again it is well worth the investment!!!

Hope that helps!

First, you have AV software (AVG) installed. Uninstall according to their instructions.

Second, Steam is taking up more than half of your processor's capabilities - so, if you want it, you will need to learn to live with that.

And, lastly, you have a slow 5400 rpm hard drive along with only 8 GB RAM - neither of which is upgradeable and which may be marginable for gaming. You need to keep in mind the processor intensive apps you want to run when buying a computer.

In addition to what Babowa mentioned, ditch Google Chrome

Google is a serious OS X/macOS resource hog.

Switch to Mozilla Firefox OR Waterfox, instead.

That model iMac is NOT even close to a gaming Mac, so don't expect miracles when gaming with this iMac, even if you switch to using an external SSD in a USB 3.0 enclosure.

Good Luck to You!

I agree it is never going to be the fastest Mac BUT the difference between the internal drive vs a USB 3.0 SSD pleasantly surprised me and saved the computer from being the next doorstop 😀 now we can use it without constant hanging.