@ Tristaan_C:
The turntimes change only by very little, but what changes greatly by RAM is the time it takes to open a city. I made a test, and when i. e. going through 100 cities, it takes 60s from an SSD while only 20s from a RAM Disk. Imagine it or not, but that can be felt, I like to describe it like HDD is click -> wait -> stutter -> ready, SSD is click -> stutter -> ready and RAM is click -> instant ready.
It's also again something different if one plays Huge maps with tons of cities and tons of units. You may think that you don't have lag, but scroll out to globe-view when having 100 cities i. e. , you will have lag, I have lag when doing that and I don't brag but only give a rough description of my notebook so that people can compare by imagination and that without envy, there'll be several players who'll have way better PCs than I have, I'm content though as you are too.
But plz don't tell me that I wouldn't know what I'm talking about, when I say that RAM Disk makes a huge difference and that 8GB are adviseable and that that will help him more and will be cheaper than a new CPU, that is the truth. CIV is yes, old, it's also badly programmed and it cannot even use modern processors. Running it from the RAM is an extra program though and the enhancement of that is major. New graphics card might also make a good deal, but only if his old one is at least 3-5y old.