For Active Garbage Collection to have an effect, the SSD needs to have periods of idle time. If the SSD is not given any idle time (ie., constant data transfers), then Active Garbage Collection will never be triggered. The drive must also have empty space available, because Trim and Active Garbage Collection both rely on the ability to move data between sectors as a part of the clean-up. For best results, keeping at least 10% of your SSD clear ensures this process runs optimally.
An SSD that is not receiving Trim commands, and where Active Garbage Collection never runs properly, will never have the cells on the drive cleaned out after data is deleted. Over time, this will lead to an accumulation of 'junk' data, which will reduce performance and can cause system freezing.
If you notice performance decreasing on the SSD, you might need to force Active Garbage Collection to run by powering the SSD on and leaving it idle for 6 to 8 hours. After that, your drive’s functionality and performance should be restored.