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Some Oracle experts say that paging is normal or even unavoidable in Oracle installation. I'll try to explain why this is not true.

• Paging increases response time. Average page-in time for single 8Kb page is measured in tenths of a second, and these tenths should be added to response time of your application as many times as many page-in events are occuring during query parsing, execution and results fetching.
• Paging sometimes dramatically increases response time. If you are using large pages for anything except non-pageable SGA, your memory becomes fragmented and in a case of paging-in of a single large page OS will be relocating small pages to construct a "hole" in a memory large enough to accomodate this large page. Page relocation consumes lot of CPU, requires excessive locking and consumes bus banwidth while moving pages across physical memory. Typical page relocation time vary depending on hardware configuration and memory pressure, but one cad add several seconds to response time of application if you are planning to keep your memory on a disk and relocate 100+ small pages to provide space for one large page being paged-in.