|Whether a system is 64 bit or not has nothing to do with the need for a pagefile. It all depends on the workload. Some configurations will need it desperately while others not at all.|
The default size of the pagefile is somewhat higher than RAM size. This is only necessary if you require a full memory dump for diagnostic purposes.
The best way to determine needed pagefile size is to monitor actual usage with Performance Monitor. Monitor the "Paging File" object, "% Usage Peak" counter during peak usage times. The initial size should be at least twice this value, with the maximum twice that.
You can also check the Commit charge. This will be the first number under the label "Page File" in Task Manager - Performance Tab. This is NOT actual pagefile usage. The second number is the Commit Limit which is roughly the sum of RAM + pagefile size. You want the peak commit charge well under the limit or bad things will happen, such as system or application failures.
A RAM drive is usually an inefficient use of memory. The system cache does most of what a RAM drive with fewer disadvantages. The are some legitimate uses for a RAM drive but not many.
Contrary to what you might read on some forums, putting the pagefile on a RAM drive is a ridiculous idea.