This paper proposes a precisely optimized sub-connected architecture to address the high power consumption and feedback-type self-interference issues in active fully-connected reconfigurable intelligent surface(RIS) systems. In this architecture, multiple RIS elements share power amplifiers, and beamforming design is carried out using techniques such as fractional programming and alternating direction method of multipliers. These can reduce the number of power amplifiers and lower power consumption. Further, a self-interference suppression mechanism is incorporated, and the optimization problem is subsequently solved using the sequential unconstrained minimization technique, which improves the system's stability and signal quality. Simulations show a 25.0%-33.3% energy efficiency gain with a 6.7%-7.4% rate reduction compared to the fully-connected architecture. Compared to existing sub-connected architectures, it achieves an 11.1%-14.2% improvement in energy efficiency and significantly reduces the impact of feedback-type self-interference, thereby validating its advantages in both energy efficiency and interference suppression.