Lifespan of 2011 iMac

I have a 27" 2011 (i7 3.4ghz 24GB RAM) iMac that I just replaced the drives (1 SSD and 1HDD) in 2 years ago. It runs pretty well now, but is just starting to slow down (and pales in comparison to my 2017 MBP). I'm considering dumping about $400 into it to add an SSD (and run both in RAID0), max out the RAM an replace the thermal sensor. I'm wondering if anyone has done any similar upgrades on a machine with close specs (specifically the age)? If so, did you get the boost in performance you were hoping for or is it just asking too much from a motherboard that old?

there are some awesome answers/comments/info here - thanks everyone... much appreciated. My main goal is to have 2 high-performing machines. Like i said, I have a 2017 MBP that is great and this iMac is still pretty good for my purposes (no gaming or 3d animation). But once this iMac starts having trouble opening big Photoshop files while I have a bunch of files open elsewhere or performing operations in Illustrator on complex drawings (which I'm just starting to see the beginnings of), it's no longer "high performing".

I really like the idea of the Mac Mini, but I can't justify the $800-$1000 expense. I could sell the iMac for probably around $500-$600 (and would have no problem justifying the $200-$400 expense), but then I'd either have to buy another large monitor or live with just 2 24-inchers... which would make me sad, I think.

I am convinced that putting the $400 into the iMac is not the best idea. So thanks for helping me get there.

Decisions. Decisions. Gotta mull it over a bit more.

Given you’ve already done the work once, you will be the best to know.

• SSD - always a great investment, plus they are almost always fungible - you can put them in newer gear with little to no degradation on speed if they still have life.
• RAM - low risk upgrade as well. Especially if you don’t need to max it. Add it only when your benchmarks prove you need it - it’s almost always cheaper to delay buying and only buy when your time to fix the software causing RAM to blow up is worth more to you than the cost of more RAM.

That being said - the $800 Mac Mini will run circles around your 2011 iMac performance-wise. Especially if your software stack can transition to 64 bit speed and run in Catalina. Some old software, when migrated to new Mac hardware simply can not run. New outclasses substantially in every other way including power efficiency, GPU, storage, CPU, memory, expansion.

So for me, the tie breaker is the display - if you love and need it, upgrade or sell to buy a newer but used 27” iMac for value. Also, I have a hunch, a lot of people will want to sell their perfectly good iMacs very soon. This includes Apple if you have cash for new and want to make a deal when the line eventually refreshes. Apple will put machines on the refurbished / clearance rack starting immediately when a new model releases and then again when they claw back all the unsold stock from distributors and retail stores globally. With this bump, I wouldn’t wait and I’d shop to price what you need before next Monday and then have your card ready to buy if you get a short-sale opportunity.

With a Mac this old - there will be a very compelling reason to choose to upgrade, decide trade up to slightly less old or “break the bank” for the latest CPU with a T2 chip. Investing in newer everything can be a great value even if you don’t go new at the $400 range.

I wouldn’t put that kind of money into this.

Why?

At the end of the day, you still have a decade old computer that cannot run the most current operating systems

• Maxing our the RAM only has benefit if you are making use of the memory. If 24GB was more than enough then 32GB won’t do a thing. It’s like having 3 cars driving on a 6 lane highway. Making it 8 lanes won’t get the cars through any faster or more efficiently

• Two SSDs in a RAID 0 configuration won’t do much You still only have a SATA III interface at 6Gb/s.

• The latest version of macOS is 10.13 (High Sierra) which is quickly becoming long in the tooth. Lots of modern apps are starting to require Mojave or later especially for the newest features.

Personally, I would still upgrade the drive to SSD as they’re very inexpensive. However, I’d run a FreeBSD desktop instead of macOS. I currently have this on a 2007 White MacBook and I’ve gotten some very useful a productive years out of something supposedly obsolete. However, this is pretty much a self-support endeavor so if this isn’t your cup of tea, you might have better luck selling the iMac on the secondary market and putting the proceeds toward a new(er) machine.

Apple is dumping Intel processors and going ARM. (An Apple Store employee prognosticated this to me in late 2018). Last two times they did this, they badly burned people who had just bought 68k or PPC Macs. They're handling it better this time by letting it be an open secret, but I would not buy a new Mac for now.

I'm writing this on a mid-2007 iMac right now, so obviously I'm OK with older hardware.

When your system starts to bog, your first stop is Applications/Utilities/Activity Monitor. It has several panes that will tell you about system health, and that will tell you what you can (or can't) do.

Leave Activity Monitor running. When the system is bogging, switch tasks to Activity Monitor and see what it can tell you. It has several "panes" which you can switch between; mind you that if you switch away from a pane for 10 minutes or so, it stops monitoring that system parameter (because that monitoring itself adds some load). So if you're starting something you expect to bog, it helps to pick a pane and have it up while the boggy task is running.

The CPU pane

will show you how hard your CPUs are working. That's pretty straightforward. If all your CPUs are maxed, that's not upgradeable, so your only path is a newer Mac. If one CPU is maxed, the process is running single-threaded, and sometimes you can do something about that.

This example shows a process that is mostly CPU-bound but slightly diskbound also (see disk example). Note that on my 2-CPU system, when it uses 50% of the chart height, it is at 100% for its single CPU.

The Memory pane

This is very important (whether you're able to upgrade or not). It shows an abstracted chart called "Memory Pressure" - that's because memory management is tricky - it doesn't just do disk swap, it also will also use ZIP/gz-style compression to compress RAM that is not used in the moment. "Memory pressure" reflects how much both strategies are affecting performance, with a simple green/yellow/red display.

In yellow/red, you will feel the lag. The upgrade path depends on what is taking memory (the task list above will state memory use). If they are other applications you don't care much about, you can close the windows or quit the apps. Watch out for apps with "memory leaks" - these take an outsize amount of memory for what they are. In fact, many apps will take a great deal less memory if you save work, close and reopen them -- this applies to many web browsers/pages.

If that's not enough, and the core apps you want to run are taking that much memory, then your path is a RAM upgrade.

In this example I kept launching apps until the system started to bog. I wasn't closing anything; the downward ticks were memory compression doing its thing. At yellow I was feeling it! At red it was hard to get the system to respond. Force-quitting Photoshop brought the system quickly back to green.

The Energy pane

It's not a concern to a non-battery Mac. It's for Macbooks, and estimates how much battery an app or browser pane is using.

The Disk pane

Reflects disk I/O. It doesn't show a "0-100%" scale because it doesn't know how fast your drives are. The display scales to the highest input and output (separately) you've seen lately.

Look at the "Data read/written/sec" numbers. You just have to learn what "normal" values are for your various drives. For instance I have some external drives that run around 20-25 MB/s when reading large files, so when I see those kinds of numbers from those drives, I know they are near limits, and my process is probably diskbound (limited by disk I/O).

On a hard drive, much of the delay is actually "seek time" - moving the head or waiting for the disk sector to come around. That's much more a problem for "many small files" than "few large files", since hard drives are optimized for large data pushes. Since you already run SSD, you have already eliminated that, so the only upgrade path is a throughput-faster SSD.

Here you can see a process suddenly max out an external drive. It's the same time as what you see on the "CPU" example (but not the "Memory" example). Notice the slight drop in CPU usage just as disk maxed out; that was the process shifting from CPU-bound to disk-bound.

The Network pane

Is telling you about LAN or Internet activity. It's usually not a big concern when you are chasing performance issues, since you expect the Internet to be slow/capricious.

Most points have been covered by other answers: but one point I would make is that whatever you do to this 2011 iMac, you're still limited to High Sierra or earlier.

So if you want to run older software, e.g. Office 2011, Creative Suite 6, etc, with as good performance as possible, then that's a reason to proceed.

But of course, with each year, the apps available to you will decrease; and your version of Safari will be 'stuck in time' as web standards move on, etc, etc.

Personally, I'd sell the old iMac on eBay, and put it towards a new Mac Mini and display. ;-)