sutiable

I Have Processor - Intel(TM) Core2 Duo - E4500 Motherboard - Intel D946GZis RAM - DDR2 1GB/667 MHz Monitor - SAMSUNG SyncMaster 740NW - 17" WideScreen I Want To Buy An Graphics Card Which One To Buy Which Is Sutiable For My System ? I Have The Budget Of 5k

Hi Friends I Wanted To Buy A 1GB DDR2 RAM So I Went To The Store I Asked For It They Showed Transcend 1GB DDR2/800 RAM. But They Asked Me Weather 800 Is Sutiable For My PC. But I Didn't Know What Is That 800. Is It Sutiable For My PC How To Know That ? Also Pls Tell Me What Is That 800...