For the last 18 months I've been running PLEX on a 2012 Mac Mini i5 2.5GHZ, upgraded with 16Gb of RAM (from 4GB) and a dual hard drive set up consisting of a 500GB SSD and the standard 500GB HD. The 2012 i5 version is a dual core model with 3Mb of L3 Cache and is still a pretty decent machine, I've ran mine 24/7 since April 2015 and it hasn't missed a beat. However recently with the adoption of the H.265 codec its started to struggle transcoding large HD files in real time so i decided to upgrade.
Unfortunately Apple no longer sells a i7 quad core model and the best they currently sell is an i7 dual core running at 3.0GHZ which is only 26% better in single core benchmarks than the model I currently own and 32% worse than the i7 2012 quad core in multi-core benchmarks. This new top of the line model costs a whopping £1309 with 16GB of RAM and a 1TB fusion drive before you even buy a mouse or keyboard. As a result of Apple's reluctance to make a quad core version I had to turn to eBay and look for a 2012 i7 2.3GHZ quad core model with 6MB of L3 Cache. I found and paid £700 for one (2.3GHZ, 10GB RAM, 256GB SSD) and they sell for this amount because people want a more powerful Mini than Apple currently produce. Apple's stupidity has keep resale value very high.
Its strange that the most powerful Mac Mini produced was released 4 years ago.
Now that i have both Mac Minis in my possession, i need to take both to bits in order to swap out the hard drives and ram. I want the 2 Hard drives from the old one into the new one and the HD from the new one into the old one and switch the 10GB ram for the 16GB ram.
Rather than bore you with lots of pics i used this the guide from iFixit. Before i did anything i used Carbon Copy Cloner to make a bootable clone of my Mac Mini's HD. CCC is a great program, It allows you to make a bootable clone of Mac OS onto another HD or USB stick or drive. This makes it very easy to move data to a new HD with the minimum of fuss and downtime.
You have to admire how Apple managed to fit all this in such little space, this is easy appreciate once you've taken one apart. It all fits together so precisely. Awesome design and engineering.
Once I'd gotten both HD's out the old mac I stripped the new one and installed them. The whole job took a hour or so. When i booted the new Mac with the old drives it was like I'd just rebooted, everything was exactly the way it was, except the system had a much faster processor! I put the old mac back together with the new HD and re-cloned with a clean install of Mac OS Sierra, ready for it to be sold on eBay to recoup some of the costs. I should get close to what i paid for it 18 months ago. Initial testing with Plex suggest the i7 is around twice as powerful as the i5. Good enough for me!