Whats the better Processor?

Hi im comparing 2 computers i want with almost identical specs except the processor. The cheaper one has a Intel Celeron 2.1 Ghz (533 Mhz FsB, 1mb cache) and the more expensive has a Intel dual Core 1.86Ghz (533 Mhz FSB, 1MB Cache).Im not really a expert at this sorta thing but the shop itant said the dearer one had a better processor but in has less Ghz. ???? HELP