No performance increase on I/O intensive operation after symlink to ramdisk
Solution 1:
What you're missing is that file writes are almost always non-blocking. So long as the OS has sufficient memory, a file write will just write to memory. The OS will flush those writes to disk as it has the resources to do so. Since you have lots of RAM, are writing small files, and have fast disk, your application probably almost never has to wait for writes to complete.
As a complete guess, I'd think that you're actually application architecture limited. You say the CPU doesn't take much of a beating, but that likely means that your application is too crude to take advantage of much of your CPU's resources. For example, if your CPU has 8 cores but your application architecture is single-process, single-thread, it can only use one core.