According to OS X 10.11 El Capitan beta 1 release notes, it will run on all hardware capable of running OS X 10.10 Yosemite.
This is great news for bargain hunters looking to buy an used Mac to save money. All 2007 or newer alumium iMacs will likely run OS X 10.11 and supported until 2019 or later.
I'm going to write up a blog post about buying used Mac to save $$.
Recently I've been looking for an used iMac to replace my Windows PC. After looking for couple of weeks, I was able to purchase a 27" late 2009 iMac for $600. This article is to help you find an used iMac on a budget, based on my recent experience. Hopefully you can get more value for your money.
Buying an OS X Yosemite Supported iMac
Why buy an iMac that can run OS X Yosemite? Unlike Microsoft Windows where software vendors supported Windows XP for over a decade, Mac software tend to drop support for older software at faster pace. For example, OS X 10.5 Leopard was released in 2007, and Google Chrome dropped support for 10.5 in 2012.
All aluminum case iMacs made in 2007 or newer is supported by OS X 10.10 Yosemite. According to OS X 10.11 El Capitan Beta 1 release notes, all Macs supported by OS X Yosemite will also run the next OS X El Capitain release. Chances are that your aluminum iMac will be supported until at least 2019 with updates and security patches. When buying 2007 or newer iMac, I recommend the following minimum hardware specs:
* 4 GB RAM (more preferred, if you buy one with 2 GB RAM you'd need to spend more money on memory upgrade)
* 250 GB HDD (more preferred)
* Keyboard and Mouse included (unless if you already have a set)
If the iMac does not have OS X Yosemite installed, it's a free upgrade from Apple, download-able directly from the App store. I recommend a clean install from USB memory stick. My 2009 MacBook ran slow after upgrading to OS X 10.10, because I had a lot of old crap installed dating back to OS X 10.5. I did a clean install from USB stick (reformat HDD), and now it runs very well.
Buying an iMac that is not supported by OS X Yosemite
Buying an unsupported Mac can save you a LOT of money, at the expense of (lack of) support and compatibility with newer software. You can easily find used G5 iMacs for under $100, and unsupported Intel iMacs for under $200 from private party sellers. At minimum, you should seek the following specifications:
* OS X 10.5 Leopard installed (unless if you have the install DVD)
* At least 1 GB of RAM (2 GB or more preferred)
* At least 160 GB Hard Disk (more preferred, upgrading iMac HDD is a pain)
* Keyboard and Mouse (unless if you already have a set)
* Pre-installed with useful software
It may be difficult to locate vintage software, so it's better to buy a Mac that already has useful software like iWork, iLife, Office 2008, Photoshop CS3/CS4, QuarkXPress, Toast Titanium 10, Final Cut Express 4, etc. pre-installed.
If you don't mind using an external monitor, consider an used G5 Power Mac (Tower). They tend to be more powerful than G5 iMacs, and have plenty of room to expand. However, keep in mind that software support for such old system will be lacking.
Suggested Pricing for Used iMac
Read the wiki article on iMac, and familiarize yourself with the models and specs. In short, white colored iMacs are not supported by OS X Yosemite, versus silver (aluminum) colored iMacs can run OS X Yosemite. If you're buying mid 2007 to early 2009 aluminum iMac, preferably you'd want one that has been upgraded to 4 GB RAM, or else you'd need to spend extra money on memory upgrades.
Here's my suggested pricing guide to used iMac:
* G5 iMac: $100 or less, preferably 2005 20" model with at least 1 GB RAM and OS X 10.5 installed
* Polycarbonate (white) Intel iMac: $200 or less. Preferably 20" or 24" late 2006 model with 2 GB RAM and OS X 10.7 installed.
* 20" Mid 2007 to Early 2009 Aluminum iMac: $300 or less. Preferably with 4 GB RAM and OS X 10.10 installed.
* 24" Mid 2007 to Early 2009 Aluminum iMac: $400 or less. Preferably with 4 GB RAM and OS X 10.10 installed.
* 21.5" Late 2009 or newer Aluminum iMac: $350 and up. Preferably with OS X 10.10 installed.
* 27" Late 2009 or newer Aluminum iMac: $600 and up. Preferably with OS X 10.10 installed.
* Late 2013 or newer slim unibody iMac: current price too expensive.
For Late 2009 or newer iMacs, the more recent the model, the higher the asking price. A Late 2009 21.5" iMac might sell for $350 to $400, versus a Mid 2014 21.5" slim unibody iMac might sell for $950 to $1000. Brand new 21.5" iMac sells for $1100 at the Apple Store, I don't see the point of trying to save $100-$150 to buy it used. But if that's what you want, then consider buying a certified refurbished Mac directly from Apple.
Where to Buy Used Macs
Online resellers: Check Low End Mac for list of current prices and resellers, such as Mac of All Trades and DV Warehouse. The price is higher than local resellers or private party, but if you live outside of major cities with very few locals selling their used Macs, this might be the only option.
Local resellers: There are a number of used Mac resellers in LA and OC area, such as Mojo Computers and Superior Computers in Santa Ana. They SPAM Craiglist, Recycler, and other online ad sites daily. If you shop carefully, you can get better prices than online resellers. One benefit of buying local is that you can inspect the Mac before buying, and most stores will offer warranty against defects.
Private party: The best prices can be had from private party on ebay and craiglist. However you are competing against many other buyers, so you need to check for sale ads frequently and contact the seller ASAP. When I was shopping for my iMac, I'd check craiglist every morning and was able to find what I want and be the first person to contact the seller. I went to the seller's apartment to inspect the iMac at noon and his phone was ringing nonstop from other buyers. Like they say, early bird gets the worm.
Safety check: If you're buying from private party, be aware that you're going to someone's house or apartment with a lot of cash. It may be safer to go with a friend or arrange the meeting at Starbucks. If something doesn't sound right or look right, stay away and stay safe.
