I would like to start by sharing something on, one of the widely debated subject in Windows world – Page file
Page files are always something debated ever since RAM become cheaper. Now a days Computers has minimum of 4 GB ram and still following the old school method of 1.5 times the RAM size for paging doesn’t make sense.
I would say if any of your machines especially servers require more than 4 GB page file we should look at the resource usage on the server and if required get the system RAM upgraded. RAM chips are cheaper and easily affordable. So any machines upto 2 GB, may be still its good to follow 1.5 times RAM size but from 4 GB to higher let us stick to 4 GB + 300 MB page file. In fact in Windows 2012 if you look at the performance tab you could see the recommended size for page file is not 1.5 times RAM. its approximately 4 GB which makes sense.
Being said that I would like to share some useful links (most importantly the link from Mark Russinovich blog). Here Mark describes page files in detail and the best approach will be to scope the servers according to the requirements. In short Page file sizing is unique to each system and cannot be generalized. Only issue leaving to system managed option is disk fragmentation of page file.