I have four fifth generation iPod touches, here's how they break down:
1. 64GB White and Blue - Still running iOS 6.1.3
2. 16GB Black and Silver - Still running iOS 7.1.2
3. 64GB Black and Slate - Running iOS 8.0.2
4. 16GB Black and Silver - Running iOS 8.0.2
Obviously, the iPod touch running 6.1.3 runs the smoothest, but 7.1.2 on the second one isn't really that bad either, but it's still not what it was when it was new. 8.0.2 on the other hand really isn't great, performance-wise. You can still use it to play music, but I wouldn't rely heavily on performance-heavy apps, at all. It's definitely sluggish and starting to not be fun to use.
Such is the way of iOS device hardware that ages.
I have four fifth generation iPod touches, here's how they break down:
1. 64GB White and Blue - Still running iOS 6.1.3
2. 16GB Black and Silver - Still running iOS 7.1.2
3. 64GB Black and Slate - Running iOS 8.0.2
4. 16GB Black and Silver - Running iOS 8.0.2
Obviously, the iPod touch running 6.1.3 runs the smoothest, but 7.1.2 on the second one isn't really that bad either, but it's still not what it was when it was new. 8.0.2 on the other hand really isn't great, performance-wise. You can still use it to play music, but I wouldn't rely heavily on performance-heavy apps, at all. It's definitely sluggish and starting to not be fun to use.
Such is the way of iOS device hardware that ages.
That's why I don't update to the newest yearly iOS unless it actually increases performance. My recommendation continues to be that people keep devices on the first iOS it comes with. Of course, many people don't notice the performance degradation; updating is fine for those people.
Why do you own four fifth gens?
Do the ones on 8.0.2 now run ok with 8.1 (I assumed you upgraded) ?