Limit of page-locked host memory

I know that page-locked host memory will lead to faster memory copy times between CPU and GPU and it can be used to overlap data transfers and kernel execution. In the guides they always say to be careful with its use, because having to much page-locked host memory may actually slow down the application.
Has anyone experience with this issue? How much page-locked host memory can be decalared? Up to the RAM available on the CPU?

Up to the RAM available on the CPU?

Probably not, your system will not be happy. I like to use it, but that’s usually in the xxx MB range - on a system with 8 GB memory.