Running logs and stuff in memory

I'm running a server with linux CentOS 6 with whm/cpanel installed. I made a website that utilizes a caching system for speed. At the moment, I'm using tmpfs (temporary file system) to store all the temporary files for the cache and even some useless logs, and after a while, it seems the more I put in the tmpfs, the slower things go. So now, I thought of using the /dev/ramX devices, but after trying one, the limit is 16M, yet I'm looking for a much larger amount, and smaller number of devices for ram because I think each ram device multiplied the size of ram for each device is the total ram used just for those devices, so I might as well somehow consolidate them all into one device and make the size bigger, but I do not know how. Internet Documentation states modifying kernel parameters but theres nothing that tells me how to limit the number of /dev/ramX devices to one or maybe two. Can anyone help?