What is the difference between GMX and dYdX?

Could you elaborate on the key distinctions between GMX and dYdX in the realm of decentralized finance and cryptocurrency? Are there any significant differences in their functionalities, underlying technologies, or target user bases? How do they compare in terms of transaction speed, scalability, and overall user experience? Additionally, how do their respective security measures and regulatory compliance frameworks differ? A comprehensive understanding of these aspects would help us make informed decisions when choosing between the two platforms.