Really wish I knew what you issueless people are doing to make the saves not noticeable. My desktop costed around 2,5k euros when it was built and the OS and EU IV is on a SSD, I even tried to move the steam cloud to the ssd but that didn't do anything at all. The first 100 years go by without issues but at some point the game will start 'stalling' for 2-3 seconds on each save. Basically goes like, see event, hit pause, wait 2-3 seconds and then the game unlocks. Internet is 100/10 but I really doubt it waits for the sync to finish because that would take like 15-30 seconds depending on the age of the game, it just stores it in the steam userdata so I'm pretty sure you could easily fool ironman mode by just copying that file and replacing it prior to exiting the game or something.
Here's a question tho, all you people who seem to have no issues past 200 years at least, is your steam installed on the SSD? Or just the games from steam, because I tried making a symbolic link for the userdata folder and installed EU IV onto the SSD from the steam folder and that did nothing at all.
Sadly Paradox's answer to this is, Buy a dedicated 2k euro machine with nothing except EU IV on it (With no guarantees of working well) AND then we won't call you a savescummer and allow you to get achievements.