Ram upgrade-match fsb?

  brummy1971 18:42 19 Jul 2009


i have a p4 with an unkown proprietory dell mobo

the mobo has 800 mhz frontside bus

it has 512 mb ram speed 533 mhz

i am going to buy some ram, 4 gb (2x2gb sticks), should i get 800 mhz ram (pc6400) to match the frontside bus of the mobo or will i not get any performance boost over 4gb of pc4200 ?


  project 90 19:10 19 Jul 2009

just get what you want really even if you get 800 and mobo suports only 533 it will run at 533 with the extra ram your putting in it will be faster any way.

i have 1066 in mine and mobo only read 800 so deosnt matter really.

have you got links for the products?

  gigagiggles 05:55 20 Jul 2009


if ram is not compatible with the motherboard and its bios, your system may end up not booting.

is there any way for you to find out what ram the mobo is capable of supporting?

if the 800 is cheaper than the slower sticks, and it works, albeit at a slower speed because the mobo won't allow it to go faster, you still come out ahead.

  Quiller. 06:02 20 Jul 2009

What is the model number of the dell machine?

  oldbeefer2 07:56 20 Jul 2009

Why not scan with the Crucial tool click here?

  brummy1971 11:17 20 Jul 2009

unfortunately it was originally a dell 5100
but some idiot of a technician installed a different mobo and vista!

crucial scan does not work

basically all i need to know is will 800mhz ram be faster than 533mhz ram on a mobo with 800 mhz frontside bus?

i thought they were supposed to match or exceed fsb but have read somewhere that 400mhz will do just as good i assume it is something to do with dual channel doubling throughput to match the 800mhz of the mobo

  project 90 20:40 20 Jul 2009

i would just get the 800mhz. if its too fast it wont matter it will run at the slower speed. you really just want to go for the cheapest tbh if your not over clocking.

  project 90 20:41 20 Jul 2009

also if you really wanna get to the bottom of it open case and take as many numbers off the mobo am sure if you google them something wil come up there should also be a name on the mobo if you poke about.

  Quiller. 21:23 20 Jul 2009

I think you need to find your motherboard details, as per project 90 for 3 reasons

1) You have 512Mb in one slot, how do you know the motherboard will support 2 X 2Gb sticks

2) some motherboards, very few, have a limit on the maximum amount of ram they can take at the full speed. One or two will only take the maximum amount of ram at a lower speed and a reduced amount at the fastest speed. It's not often but you should check.

3)What memory density the motherboard will take. Get it wrong and the memory might not even boot the machine.

Try SIW to get the motherboard or open the case as project 90 suggests.

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