The iMac 27″ 2017 with Retina 5K display can accept up to 64gb of 2400Mhz DDR4 Memory.

There’s four slots to choose from so you have some options when upgrading – from as little as 4GB of RAM all the way up to 64GB of RAM.

SSD drives can be installed in this Mac but it’s a task to be sure.

Check RAM Prices for The iMac 27″ 2017 with Retina 5K display

eGPU.io is a website dedicated to all things dedicated to using an external GPU with your computer:

 eGPU.io is the definitive eGPU community formed by enthusiasts

Our mission is to make eGPUs simple and accessible to everyone

The Lenovo Thinkpad x230 with a price as low as $100 is a great computer if you can live with a model that’s five years old and a RAM upgrade will go a long way. Unlike the X240 that maxes out at 8GB you can install 16GB in the X230 for under $100. Add an SSD drive for another hundred and you’ve got a great maxed out i5 computer for as little as $300

The 2010 Apple MacBook Air sells for about $250.00, but has the ram soldered on so you’re kind of screwed when it comes to memory upgrades for this model but there are a few upgrades you can do to this such as battery, ssd and replacement chargers can be had for this MacBook Air in both 13 and 11 inch sizes.