I read the solution for PS and have gone to Edit, Preferences, general, Performance - at this point I'm supposed to see Memory and change the amount numbers. I don't have that option - anyone know where it is in PSE 18?
It can't be in Elements, it's in Windows. The Windows 10 (1803) update removed from your computer some code used by recent Elements version to manage memory. Microsoft makes it nearly impossible for you to get back to the previous Windows 10 version, which would solve the problem. Immediately after that update, Adobe provided a workaround to solve the issue. The Windows registry holds a number of settings including Application specific ones to manage memory. The detailed step by step procedure in this help paper: https://helpx.adobe.com/photoshop-elements/kb/integer-50-8-required-closest-value-inserted-photoshop... It's about modifying the Windows Registry via the Microsoft 'regedit' tool.
Photoshop doesn't have an adjustment for this Also, you'll need to mention which Operating System (Windows?) and for what reason you want to change the memory. I'm not sure if you're talking about changing the Virtual Memory or RAM, but I'd first need to ask how technical are you? It's not easy to know what you're doing with the Virtual Memory or a cache change. It can make your drive space smaller. And, you cannot change the RAM unless you change the hardware inside your computer.