In general faster FPS is down to:

1. A higher frequency CPU
2. A better graphics card
3. Higher frequency memory and mo'bo
4. Low latency and high bandwidth between ALL MP players and the dedicated server
5. Keeping active AI to less than 120 units at any one time and managing your ALiVE mission appropriately.

Faster loading times

1. Faster storage i.e. SSD
2. More bandwidth between you and the dedicated server

Reduction in texture/model "popping", better resolution for long view distances

1. 64-bit Arma engine utilising more system memory (greater than 2GB).
2. Faster storage i.e. SSD

Improvement in ALIVE
1. Moar volunteer developers!