If you’re using an SSD and you noticed low FPS, try to delete some files and free up some space to fix the problem. I initially installed Total War Rome Remastered in my old SSD (Solid State Drive) and ironically, I noticed severe FPS drop there compared to when the game was ran in may hard disk drive. However, there may be cases when the hard drive fails to respond fast enough that the game suffers a sudden drop in frame rate for a second or two. Most of time, this happens without any noticeable issue, if your hard drive works normally.
Games may sometimes need to read or write off the hard drive during game play. If your machine has insufficient RAM, it can lead to a drop in frame rate in games as the system will have to pause in order to manage the memory.
Total War Rome Remastered requires that your PC has a minimum of 6GB RAM (but you should preferably want to meet the recommended 8GB RAM). RAM, also known as memory, is one of the system requirements that every PC player must know, especially when troubleshooting performance issues.
If you have an old Intel core processor, you should consider upgrading to a more powerful one.