As virtualization becomes a key technique for supporting cloud computing, much effort has been made to reduce virtualization overhead, so a virtualized system can match its native performance. One major overhead is due to memory or page table virtualization. Conventional virtual machines rely on a shadow mechanism to manage be handled by the guest itself without triggering VM exits. However, the hardware assists do have their disadvantage compared to the conventional shadow mechanism -the page walk yields more memory accesses and thus longer latency. Our experimental results show that neither hardware-assisted paging (HAP) nor shadow paging (SP) can be a definite winner. Despite the fact that in over half of the cases, there is no noticeable gap between the two mechanisms, an up to 34% performance gap exists for a few benchmarks. We propose a dynamic switching mechanism that monitors TLB misses and guest page faults on the fly, and dynamically switches between the two paging modes. Our experiments show that this new mechanism can match and, sometimes, even beat the better performance of HAP and SP.