The only way to answer this is to set up some performance monitors while you play, to graph the CPU/RAM/Page file usage
Since a reinstall helped, I'd hazard a guess that you were being RAM limited, due to background services and bloatware. This means the page file was being hit heavily and an SSD would definitely have helped.
If you can upgrade your RAM, do so, then put an SSD in when you can afford it. Your PC will last a lot longer before it feels like it needs a reinstall again. Even if it doesn't make a lot of difference in FM2011, It's a great upgrade that makes a big difference to the general 'feel' of the machine on the desktop.