Celeron 400MHz + Which Memory?

[COJOi]

I would like to buy a Celeron 2.6GHz 400MHz FSB for my mother's Intel system but I have a few questions first.

Which RAM will work with this processor? If I buy PC3200 at 400MHz will it be in sync? I mean will the 400MHz FSB run in sync with the 400MHz RAM? Is there such a thing?

If I were to buy PC2700 RAM at 333MHz will it underclock itself to 200MHz?

Thanks for any help.

Note: I know an AMD 2500+ is better but there really is no need. I mean come on, it is for my mom.

[Omardeth]

there is no need for pc3200 for a 400fsb intel cpu .

it goes by a multiplier of 4 so pc2100 will be more than anuff . pc2100 =133fsb

[John Prophet]

The better question might be "which RAM is right for the motherboard?"

Do you happen to know the motherboard brand and model??

[COJOi]

I am a little confused. PC2100 is 133 because you divided 266 by 2? If I multiply 133x4 I get 542 proving that you are correct that it will be more than enough since the FSB is only 400. This raises another question though. I have a system running an Asus A7V333 with an Athlon XP 2100+ and 512MB of PC2700. Do I really need the PC2700 or should I switch to 2100 since the FSB of the 2100+ is only at 266MHz?

Prophet, I do not know the model of the board. I bought the system from Dell. I know it is an Intel board with an Intel 875P chipset.

[John Prophet]

you would never switch from pc2700 to 2100. If anythign the pc2700 will just run at the slower pc2100 speed.

All the numbers can get confusing.

pc2100 is another way of saying DDR266 and PC2700 is another way of saying DDR333

The 2100 or 2700 etc refers to the "bandwidth" of the memory.

For example PC100 SDRAM = 800 MB/s because of the 8bytes width x 100mhz

so with DDR it became 100mhzx8MBx2(for DDR)=PC1600

so for pc2100 it is

133 x8 x2 = 2100 (actually 2128 but who's counting?)

PC2700= 166 x8 x2= 2656

pc3200= 200 x8 x2 = 3200

-----------------

also lots of boards have the ability in the bios to run the cpu clock and ram clocks at different speeds (sometimes called "asynchronously")

so if you have a celeron with a 100mhz fsb you could still run pc2100 with a 133fsb....that way you are getting the most from the memory


in your case pc2100 would probably be ok or pc2700 which would just "clock down" to pc2100 speeds.

[HeadBand]

all you really need is pc 1600 but that is probally mor expensive than pc2100 and that would also give you plenty of oc headroom

also i would just keep the 2700 because you already have it and that will also give you some oc headroom...if you want

[RayH]

Check the manual that came with the motherboard or check with www.crucial.com You may have limits or certain types of configurations that you have to follow, i.e. single or double sided.