Try the SAS support http://support.sas.com/ website and it's search facility or use the Google advanced search argument listed below:
sas performance large sequential input site:sas.com
There are OS platform considerations; disk, memory considerations depending on your SAS environment. Also, you really have not explained the intended start to end processing (DATA step, PROC IMPORT, what analysis PROC(s), if any, etc.). With such an open-ended question, you may be better off starting with the SAS support website resources for reference and review, then come back with a more specific set of questions after you get started writing your SAS program to read the "huge" (a relative term to one individual's perspective) data.