How to activate cache for variables

[gwlucastrig]

I am processing a NetCDF file containing a Variable with dimensions 10800 by 21600, and chunk size 1350U, 2700U. I wish to scan it in row-major order. It works like a charm when I activate the cache:

z.setCaching(true);

But if I do not make this call, the process absolutely crawls (rather than taking 10 seconds, it takes nearly an hour) . Well, using setCaching() is awesome, except that the method is deprecated. As far as I can tell, there is no other way to enable the cache. I tried:

z.createNewCache();

which does not make any difference.

So, my question is what am I missing and what is the recommended way to proceed?

Thanks.

P.S. I am using cdm-core version 5.6.0. The data file in question is the ETOPO Global Relief Model available at the NCEI THREADDS Server