Can anyone explain me the CPU/RAM ratio divider ?

[Bennethos]

Can anyone of u guys explain me how to understand the number ... lets say 3:4 ?

Im sure it has to do smthing with the fsb etc...


Thx

 

[Stumpjumper5200]

Do the math, first number represents the CPU (fsb speed) the second is the ram.

Mine is 145 fsb with a 4/5 mem divider which means:

(145 / 4) * 5 = 181.25 * 2 (for DDR ram) = 362.5 mhz

 

[WyrmMaster]

Also, its pretty much useless (with AMD atleast) because it increases the ram bandwidth without increasing the CPU bandwitdh, so the extra doesnt get used. Basically it lets you run the ram at a different speed than the fsb.

 

[Tipycol]

But if you overclock, that should get rid of that problem

 

[Stumpjumper5200]

Yeah, that's my major gripe I have with AMD, the memory bandwidth isn't what it could be.

If AMD could boost the fsb like Intel does, as well as get the clock speed up there too (while keeping the performance per mhz it's known for)..........well, Intel would be toast

 

[Tipycol]

Hehe, would've liked to have seen the new XP's have a fsb of 200 instead of 166
Course only one available board (Asus A7N8X) "could" officially support it right now, and JEDEC doesn't have official support for DDR400 (although this doesn't bother me I know it bothers some people)

 

[Stumpjumper5200]

Yeah, who cares about jedec? haha

Oooooh, JEDEC doesn't support it! Jedec needs to get off their @$$ and certify it so the non-believers can enjoy some real bandwidth

 

[cullam3n]

Is there anything wrong with this:

2.5*162 = 405mhz?

That's what I run at.

-PC

 

[Tipycol]

There's nothing wrong with running it that way, using the mem divider to increase the memory bandwidth. The thing is that the cpu will only use the bandwidth as if it was DDR324, since that is the fsb.

 

[Nildey]

so shouldn't you have the ratio at 1:1 at all times then since the CPU doesn't use the extra bandwith anyway and you are just OCing your memory unnecessarily?

 

[DipStickTony]

On an amd system yes...since the athlon cant utilize the extra bandwidth.

On a pentium4 try and get the memory as fast as possible since they have alot more headroom for extra bandwidth.