The updated versions are more accurate, which comes at some cost of speed sometimes, but the devs try to balance it out with speed improvements.
You're probably getting a CPU bottleneck form the more accurate code. Your CPU is starting to fall towards the lower end of CPUs (in Dolphin) without being overclocked. Can you overclock your CPU more?
The games did not run perfectly. They were buggy and prone to random crashing that has been fixed. However, if you are content with getting better speed versus getting more accurate and stable games then you are free to keep using the older versions. But if you have a bug or issue, you'll have to upgrade to the new versions.
You're probably getting a CPU bottleneck form the more accurate code. Your CPU is starting to fall towards the lower end of CPUs (in Dolphin) without being overclocked. Can you overclock your CPU more?
The games did not run perfectly. They were buggy and prone to random crashing that has been fixed. However, if you are content with getting better speed versus getting more accurate and stable games then you are free to keep using the older versions. But if you have a bug or issue, you'll have to upgrade to the new versions.

