1. Collection cannot happen at any time. It's not like the GC just decides to do a collection. It happens on allocation. If you don't allocate, you don't collect.
2. Most garbage collectors don't scan the entire heap. You don't scan dead objects. You could have the larges heap in the world, but if you, at collection time, only use 100mb worth of ram, you only ever scan 100mb. Copying collectors also gives you memory defragmentation for free, which ensures quick allocation times, something ARC cannot do.
1. Collection cannot happen at any time. It's not like the GC just decides to do a collection. It happens on allocation. If you don't allocate, you don't collect.
2. Most garbage collectors don't scan the entire heap. You don't scan dead objects. You could have the larges heap in the world, but if you, at collection time, only use 100mb worth of ram, you only ever scan 100mb. Copying collectors also gives you memory defragmentation for free, which ensures quick allocation times, something ARC cannot do.