Downside of using ref keyword when passing objects

While doing code review for a project, I came across a method in a class where the developer had used code which is somewhat similar to the lines below:
Savel(ref ClassA objA, ref ClassB objB)
{
}


I know very well that it makes no sense in using ref keyword when you are passing objects; as object by default are reference types, but I am interested to know if there is any performance hit if somebody does use ref when passing object also.


Any help is deeply appreciated.

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