Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
In article <422157c4$1_3@alt.athenanews.com>,
robert@cooljazzcreatives-dot-com.no-spam.invalid (lanstrad) wrote:
> Thanks everyone.
>
> Ben : You mentionned the P4B533 borad to be limited to the 266Mhz DDR.
> Do you think this will still be the case considering this system is a
> Pentium 4, 1.62 Ghz ? Or do you mean no matter the cpu, this ASUS
> board *has* these limitations ?
>
> Thanks,
> Rob
On processorfinder.intel.com , the only 1.6GHz Pentium4 processors
are FSB400. The memory used with those can be DDR200 or DDR266
(1:1 or 3:4 setting in the BIOS). If a FSB533 processor was used,
only the 1:1 option should show up, which is DDR266 rate and is
satisfied with PC2100 or any faster memory. (This is because memory
is backward compatible, and PC3200 memory can be turned down to
PC2700, PC2100, PC1600. So a PC3200 memory can still function
properly - it is just not living up to its full potential. PC3200
memory is also easier to sell later.)
In other words, Intel intended the memory interface to do no more
than DDR266, which is satisfied by PC2100 memory or faster.
Processor
32bit | 64 bits
66MHz FSB400 | 100MHz x 4 = 3.2GBytes/sec
AGP4X |
1066MB/sec | 64 bits
Video --------------- Northbridge ------------------- Memory
| 100Mhz or 133MHz
8bit | x2 = DDR200 or DDR266
66MHz | = 1600MB/sec or 2100MB/sec
x4 | = PC1600 or PC2100
=266MB/sec |
|
Southbridge ----------- PCI
32bitx33MHz
=132MByte/sec
If you decide to overclock the board, you might find the maximum
processor clock would be about 160MHz. That is FSB640. Using a
1:1 memory setting, the memory would run at DDR320, and a PC2700
or faster memory could perform at DDR333 to meet that speed
setting.
In summary, you can buy any memory that meets the speed the board
runs at, and the memory can be faster if you want, but it just
won't get to run at its maximum clock speed. If you bought a PC3200
memory, it can be dialled down to any board speed required. Even
a PC2700 memory fully meets the needs. And if no overclock is
planned, a PC2100 memory will do the job.
The Northbridge only has control signals to drive four ranks
of memory. That is equivalent to two double sided memories.
Even though there are three slots, only the first two can be
used when they are filled with double sided memories. This is
because slot2 and slot3 share control signals and are cross
wired. When slot 2 has a double sided DIMM in it, all the
control signals are used, and there are no unique ones
left on slot 3 when that happens. If a double sided stick
is put in slot 2, and any kind of stick is put in slot 3,
they will fight (and burn) one another. See section 2.5.2
in the manual, for a table of configurations.
To answer your original question, you can use both of them,
as the slowest of them fully meets the fastest speed the
memory bus can do (without overclocking), which is DDR266.
If you were a crazy overclocker, then you could use just
the DDR400 stick of memory, which will comfortably allow
you to try DDR320 memory rates. (The DDR266 might not like
running at DDR320 if you force it.)
HTH,
Paul
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