A potential decrease in mining speed may be caused by the following reasons:
Changes in the total number of active users. The number of clients using the miner simultaneously is constantly changing. To ensure stable operation of the service and its availability to all users, mining resources are distributed across multiple servers, which may lead to a temporary reduction in overall speed.
Reduction in trading turnover. Mining speed directly depends on the trading activity on the account. If the trading volume decreases over the last 30 days, the speed is automatically reduced. For more details, please refer to this article.
These two factors are interconnected and can affect the final mining speed.