Database Software

I'm currently testing whether using an OLAP cube is a viable solution in our case. Here's an overview about the data for the first test setup:

3 dimensions:
- one time dimension
- one small dimension (4 levels)
- one large dimension (5 levels)

Items in each level of the large dimension:
1st level: 27
2nd level: 246
3rd level: 1.889
4th level: 383.434
5th level: 1.348.869

While the small dimension can be easily handled by the OLAP cube, loading the large dimension data takes too long (It has already been running for over 4 hours and is still running). Since the dimension data changes regularly and will be even larger in the real setup, this is not acceptable.

Is there a way to significantly increase the dimension data load speed, or is an OLAP cube not the right solution for this problem? Or is there anything else I'm doing wrong?

What during the loading process requires such a lot of processing power?

Any suggestions or further reading material are welcome.

Thanks,
Karl