Regarding upgrading ram

[hapdtop]

My desktop motherboard (intel 946gz) supports ram only upto 667 mhz, max 2gb in a slot (total 4 gb). I wanted to upgrade it. But 667mhz ram is hardly available in the market. can I use single 4gb 800mhz stick in a slot
Thanks

[ico]

yes. 800 mhz will work fine. It will downclock to 667 Mhz.

[hapdtop]

Will there be a problem if I use 4 gb single stick on each slot

[Sam]

^^ most likely PC won't boot and will beeps.

most likely your mother's chipset support 4Gb maximum through a single channel. then you can't. even if it does work, you'll get 2Gb max.