LLVM is a free, open-source compiler framework for programmatically generating machine-native code. Developers nowadays are increasingly embracing LLVM to develop new languages or modify existing ones. LLVM-based compilers enable shorter build of compilers that are portable across various platforms, easy to maintain, and extensively optimized for the target systems. Intel oneAPI moved to an LLVM infrastructure with C (icx) and C++ (icpx) compilers in the 2021.3 release and a Fortran compiler (ifx) in the 2023.0 release. According to Intel, the LLVM-based compilers are packed with advanced language features and deliver the absolute best performance for various applications on Intel architectures. The LLVM-based Intel compilers have been extensively tuned for the 4th Gen Intel Xeon Scalable processors (code-named Sapphire Rapids) and Intel Xeon CPU Max Series (code-named Sapphire Rapids HBM) and the Intel Data Center GPU Max Series (code-named Ponte Vecchio). In this work, I aim to explore the features and performance of LLVM-based compilers compared with legacy compilers on three machine architectures, i.e. Sapphire Rapids with DDR5, Sapphire Rapids with HBM, and Intel Cascade Lake. To my best belief, this is the first extensive study that uncovers the potential of LLVM-based Intel compilers with eight scientific representative codes and demonstrates up to 17% performance improvements with Inter Fortran compiler (ifx) on Intel architectures.