Nope, incorrect.
Even after the GPU & CPU upclock, Microsoft is significantly behind the PS4 in raw HW performance. To compound their mistake, Microsoft chose a high overhead 3 OS design for the Xbone (Hypervisor + Windows partition + game partition). Sony choose a low overhead single OS design (FreeBSD Unix). If you could run them on identical HW, you would find the Sony PS4 OS actually is FASTER than the Microsoft Xbone OS version while running games.
Microsoft realized they delivered underpowered HW, so they spent time working on upclocking. Microsoft has also realized the OS is slow, so they are working to improve performance by reducing some of the reservation, but this won't happen till months after launch.
What Digital Foundry forgot to mention is that Sony continues to improve performance of it's OS over time too. And Microsoft's 3 OS design will never be as fast as a single OS design.