Microring modulators are the most fundamental and crucial building blocks for next-generation big data applications, including optical interconnect, photonic computing, and optical wireless communication. However, achieving exceptionally fast modulation rates for microring modulator remains a formidable challenge due to the photon lifetime limitations and lumped electrode architectures. In this work, we propose and experimentally demonstrate an ultra-high-speed microring modulator on a silicon nitride-loaded lithium niobate on insulator platform. By integrating low-loss Euler-bend waveguides with fully symmetrical capacitively loaded traveling-wave electrodes reinforced by a dummy waveguide, the device achieves a record-breaking modulation rate of 517 Gbps (200 GBaud PAM6). This exceptional performance is accompanied by an electro-optic bandwidth exceeding 110 GHz and an ultra-low energy consumption of merely 1.5 fJ/bit. To demonstrate the performance and application prospects of this modulator, we successfully verify its capability to accelerate feature extraction at a modulation rate of 40 GBaud in photonic computing and support breakthrough wireless multi-target communication with a single-channel capacity of 360 Gbps (180 GBaud PAM4), highlights its transformative potential across a broad spectrum of next-generation photonic systems.