Memory resident tables

I'm resending this in case there are any other takers ... Art, any ideas? Hello iFolks, I have a question about the new functionality offered in the newer versions of IDS, where tables can reside in memory. If you have really good cache rates can an engine still benefit from this feature? I suspect checkpoints would perform better, as in not necessary for the hard drive writes, but it would seem like a marginal advantage to overall performance. So what is the real benefit if your cache rates are already high? In addition, has anyone heard of segmenting tables between memory and disk with this feature? It would seem hypothetically possible. Any ideas or comments would be appreciated.