P4C800 Deluxe memory timing settings <---INFO

  • Thread starter Thread starter Noozer
  • Start date Start date
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Noozer

Hey all!

Just thought I'd mention something about the BIOS timing setting for your
memory. The BIOS shows the manual settings as "266Mhz, 320Mhz and 400Mhz".
This isn't entirely correct. They really should read "3:2", "5:4" and "1:1"
as chaning the CPU FSB will also affect the DDR timing.

For example...
My 2.6Ghz P4 runs a stock FSB at 200Mhz. Choosing the 266Mhz setting will
give me 266Mhz DDR timings: 200FSB / 3 * 2 = 133 (times 2 for DDR) =
266Mhz). Choosing 320Mhz gives me 320Mhz DDR timings: 200 FSB / 5 * 4 = 160
(times 2 for DDR) = 320Mhz.

If I clock my P4 to a FSB of 248Mhz it runs at 3.25Ghz. Choosing the 266Mhz
setting will give me 330Mhz DDR timings: 248 / 3 * 2 = 165 (times 2 for DDR)
= 330Mhz. Choosing 320Mhz in the BIOS gives me 396Mhz DDR timings: 248 / 5 *
4 = 198 (times 2 for DDR) = 396Mhz.

These timings were verified using Sandra 2004. Benchmarks did see
improvments with the faster speeds.

So remember, the BIOS choices shown are based on a stock FSB of 200 and
you'll have to calculate the real memory timings if you change your FSB.

Hope this isn't too confusing.
 
On Sun, 04 Jan 2004 18:35:50 GMT, "Noozer" <[email protected]>
wrote:

excellent post... as a newbie to this mobo it took me a day to figure
that out. I was used to the automatic positioning of the memory
figures in the bios of the P4PE mobo...
 
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