P4S533 - Max RAM modules installed?

  • Thread starter Thread starter Matt
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Matt

Hello, I have an Asus P4S533 (an older, orginal one). The manual
states that only 4 banks of RAM may be used when operating in PC2700
mode.

Does anyone have any experience of what would happen if I installed 6
banks? I would like to install 3x512MB, but unless you spend LOTS of
$$$, 512MB cards are 2 banks.

I have been told the reason this isn't allowed _could_ be due to power
requirements, or other more serious issues involving synchronization.
On the other hand, I've been told that Asus makes some fine borads,
and it may be able to handle it. Has anyone installed more than 4
banks at PC2700 or have any more information? Thanks!

--Matt
 
Matt said:
Hello, I have an Asus P4S533 (an older, orginal one). The manual
states that only 4 banks of RAM may be used when operating in PC2700
mode.

Does anyone have any experience of what would happen if I installed 6
banks? I would like to install 3x512MB, but unless you spend LOTS of
$$$, 512MB cards are 2 banks.

I have been told the reason this isn't allowed _could_ be due to power
requirements, or other more serious issues involving synchronization.
On the other hand, I've been told that Asus makes some fine borads,
and it may be able to handle it. Has anyone installed more than 4
banks at PC2700 or have any more information? Thanks!

--Matt
Click to expand...

It isn't power - the issue is called "signal integrity". Each
DIMM is a stub load off a transmission line - the more DIMMs
added, the worse the signals look electrically.

The old rules of thumb were:

On a single memory bus, you can run 1 DIMM at DDR400 (PC3200)
On a single memory bus, you can run 2 DIMMs at DDR333 (PC2700)
On a single memory bus, you can run 3 DIMMs at DDR266 (PC2100)

Some slight improvements in memory bus design now allow
two DIMMs at DDR400 on some motherboards, but these are just
rules of thumb, as some boards will allow more loads than
others. For example, the 875/865 Intel chipsets have the
series damping resistor inside the Northbridge, rather than
as a resistor on the motherboard, and that means, in theory,
the resistor value can be trimmed at runtime by a driver.

Your board has control signals for 6 banks of memories. The
P4B533 and the P4PE are examples of boards that only have
control signals for 4 banks, so no more than 2 DS or 1 DS and
2 SS sticks can be used on one of those boards. Your board
has control signals for 3 DS sticks, and only the "speed rules"
are an issue.

If you put 3x512 in your board, the worst that should happen, is
you'll need to reduce the memory speed to get it to work. In
some Asus BIOS, the BIOS actually cranks the clock down when it
detects a certain number of banks of memory installed. You
only need to drop the clock until memtest86 or memtest86+
find no errors.

For a single DIMM, the best slot is furthest from the processor.
For two DIMMs, slot 1 and 3 are best (slightly better than
using 2 and 3). If you have 1 DS and 2 SS DIMMs, put the double
sided one furthest from the processor. (If you have a P4PE,
P4B533 or other 4 bank/3 slot motherboards, check the manual
and follow the population rules there.)

HTH,
Paul
 
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