I'm not sure about the time.
Using the Windows MEMORY DIAGNOSTIC tool, it took 2H38m on my defunct Pentium G645, 6GB RAM, test mix extended, cache on, pass count 5.
Hence I estimated 8 hours if I had chosen 15 passes (that's the maximum)...
I didn't check the time with the other tools.
In the past, it was possible to modify the passes on memtest86: over 4, like it is now.