memory speed not correct

  Leslie-212488 18:59 20 Jan 2005

mobo: asu A7N8X-X
PC-3200 512MB ram
sempron 2600, FSB 333MHZ.

in the bios is says that the memory freq: 200MHz.
The CPU external clock: 166 Mhz (FSB)
Mem freq:[ BY SPD]
What memory frequency should be displayed
is it 166 MHz as the (FSB) or 333MHz 2 time the FSB.
if i set The mem Frrq: [sync], will the resulting freq read: 333, 166, or 400MHz.could this affect the overall speed of the CPU.
which FSB should i use. 166 clock or 333 CPU
if i want to directly match the freuencies by using the % which FSB do i use to resuce the freq of the memory.i have trolled the net for info, but still confused. need some input, please.

  dan11 19:41 20 Jan 2005

Your memory and cpu speeds are right. Memory is 400Mhz and cpu is 166Mhz x 2 = 333Mhz.

If you want to use the memory frequency ( by spd) then yours will be 120%. The rreason for this is your memory is running 20% faster than your cpu. The cpu speed is always 100% and the speed of the memory is measured below, equal (syc) or above the cpu speed. ie.

166 x 120% = 199.2 Mhz

near enough 200Mhz.

  Leslie-212488 10:18 21 Jan 2005

dan 11,
are you saying, for the [by SPD] setting, whats displayed is 200MHz ?
if i change it to[sync], will it then be 166MHz?
which is the better setting? or do i have to use the %. if so what do i set it to.

  dan11 12:52 21 Jan 2005

Yes, the [SPD] setting is correct.

It is showing the cpu @ 166Mhz and the memory @ 200Mhz.

If you picked the [sync] option, then this would drop the memory speed down to 166Mhz to match the cpu. You see the Sync option is to synchronize the cpu and the memory to the same bus speed.

You only need to use the % options if the [SPD] is incorrect. Or like me you like to twiddle with the options:-))

Hope this throws a bit of light on the subject for you.;-)

  dan11 12:55 21 Jan 2005

"which is the better setting? or do i have to use the %. if so what do i set it to. "

The setting you have now [SPD] is the best performance option you have.

  Leslie-212488 18:04 21 Jan 2005

yes, i think i am finally getting it, but dont you want the CPU and the MEM to be in SYNC for the best performance? If the memory is 20% faster than the CPU, wont that mess up the timing?

  dan11 18:44 21 Jan 2005

In older motherboards, it WAS important to synchronize the cpu and memory to the same bus speed. New motherboards have advanced a lot and different bus speeds for cpu and memory are just one of them. You can drop the memory speed down to 166Mhz if you want to, [ sync ] or 100%. These give exactly the same speed of the cpu to the memory.

By dropping it down to 166Mhz, you would put a little less strain on the memory chips but you do get the best performance with the 200Mhz.

The choice is yours, both will be fine.:-)

  Leslie-212488 21:25 21 Jan 2005

thanks for that explaination, now i understand it completely.the CPU FSB determines the mem clock speed. if the Memory is faster, it does not matter. but if the memory is slower the CPU will slow down to the memory's speed. if my memory was 266MHz i would not be able to set the FSB to 166-333MHz. it would need to be 133MHZ and the memory freq would read 133. this is because the memory could be run at 333MHz. so my 2600 CPU would be running at 133*11= 1463MHz instead of 1833MHz.

  dan11 22:36 21 Jan 2005

Not quite right. You see the memory frequency [by SPD] in the bios has a variety of settings. All the percentage options are variants of memory speed to the cpu speed. i.e. 50% 60% 66% 75% 80% 83% 120% 125% 133% 150% 166% and 200%

So if you use a cpu with a clock speed of 166Mhz (333). then this will always be 100% so you have to match the speed of the cpu to the memory.

So for your example, using memory of 133Mhz(266) would mean you had to have the setting @ 80%, because 133mhz is 80% of 166Mhz. This would mean that the cpu would run at it's right 166Mhz speed and the memory would run at it's fastest speed 133Mhz.

Hope that didn't bore you to much.;-)

  Leslie-212488 08:01 23 Jan 2005

error, the penultimate line should os read"the memory could not run at 333MHz"

so the CPU would still run at its native FSB at 166, but 80% slower, to compensate for the memory speed of you dont have to lower teh CPU FSB to 133MHz.

thanks again for putting me straight.

  dan11 16:05 23 Jan 2005

I can't be making this very clear.:-)

The cpu will ALWAYS run at it's true speed.i.e. 166Mhz.

It is only the memory that will run at a percentage of the cpu speed.

so if you were to use 133 Mhz ram, with a 166Mhz cpu in your board. The cpu will STILL run at 166Mhz, but the [SPD] setting would be 80%.

This is because 133 divided by 166 = 80%

Your present ram is 200Mhz, so yours is

200 divided by 166 = 120%

and 166 ram

166 divided by 166 = 100%

Hope this clears things up.

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