I recently bought XPS.
My order specs were: i7-8550U Processor (8M Cache, up to 4.0 GHz).
However, I've received a product in which system details are: i7-8550U CPU @ 1.80GHz 2.00 GHz.
Are they both (order and product specs) same?
It's the same thing. Intel has just made things confusing, but 1.8 GHz is the base speed of the CPU. 2.0 GHz is the "TDP-Up" frequency that the system manufacturer (or sometimes the owner) can enable by increasing the power delivered to the CPU, and it looks like Dell has done that. 4.0 GHz is the maximum Turbo Boost frequency that the CPU will sometimes use automatically if most of the cores are idle and there's enough power and the processor isn't too hot. You can see all of these figures and all other specs of that CPU on Intel's official page here: https://ark.intel.com/products/122589/Intel-Core-i7-8550U-Processor-8M-Cache-up-to-4_00-GHz