DDR2 memory---must it be bought in pairs?

On Sun, 24 Oct 2004 11:19:08 -0400, TheKeith <no RemoveThis @spam.com> wrote:

 >I'm building a new computer based on the Intel 915g chipset and the
 >motherboard I chose (http://tinyurl.com/5s4pk) requires DDR2 memory. I'm
 >a bit confused about how to purchase memory since the last computer I
 >built uses SDRAM. Does this stuff have to be bought in pairs for some
 >reason? I noticed on newegg, you have the option of purchasing single
 >mem modules or modules in pairs. I can only imagine that the reason they
 >sell them in pairs like that is because that's the way it has to be
 >installed? Is this true--could someone please explain? Thanks.

The chipset supports running a single dimm - at commensurately reduced peak
memory bandwidth. (Nothing is for free, son

The only question is whether the motherboard manufacturer cobbled the bios
bits to support that option. And the answer to that is the answer to the
question of "must DDR2 dimms be purchased in pairs".

btw, if the question had been "*Should* DDR2 dimms be purchased in pairs?" the
answer to that is clearly "Yes"...

/daytripper<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: DDR2 memory---must it be bought in pairs? 

TheKeith wrote:
 > I'm building a new computer based on the Intel 915g chipset and the
 > motherboard I chose (http://tinyurl.com/5s4pk) requires DDR2 memory.
 > I'm a bit confused about how to purchase memory since the last
 > computer I built uses SDRAM. Does this stuff have to be bought in
 > pairs for some reason? I noticed on newegg, you have the option of
 > purchasing single mem modules or modules in pairs. I can only imagine
 > that the reason they sell them in pairs like that is because that's
 > the way it has to be installed? Is this true--could someone please
 > explain? Thanks.

Most Pentium 4 motherboards require pairs of DIMMs of the same size for one
reason -- dual-channel memory. Dual-channel is a quick way of saying that
the DIMMs are being interleaved. Interleaving is when you use one DIMM, and
while it's busy, you can then being to use the second DIMM at the same time.
It doubles the through throughput of the DIMMs.

Yousuf Khan<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: DDR2 memory---must it be bought in pairs? 

On Sun, 24 Oct 2004 11:19:08 -0400, TheKeith <no.DeleteThis@spam.com> wrote:

 >I'm building a new computer based on the Intel 915g chipset and the
 >motherboard I chose (http://tinyurl.com/5s4pk) requires DDR2 memory. I'm
 >a bit confused about how to purchase memory since the last computer I
 >built uses SDRAM. Does this stuff have to be bought in pairs for some
 >reason? I noticed on newegg, you have the option of purchasing single
 >mem modules or modules in pairs. I can only imagine that the reason they
 >sell them in pairs like that is because that's the way it has to be
 >installed? Is this true--could someone please explain? Thanks.

If you're confused with the memory choice, which others seem to have sorted
out, you may also need to be aware of the need for the latest ATX12V V2.0
power supply with a 24-pin main power connector to the mbrd... apparently
to do with the new Prescott and PCI Express power reqts. I see very little
about this at NewEgg and from what I can see most cases still come with
ATX12V V1.x P/S. There are 20-24-pin adapters available but I've no idea
how compatible that makes the system. Just another little niggle to bother
us all.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: DDR2 memory---must it be bought in pairs? 

On Mon, 25 Oct 2004 03:45:19 -0400, George Macdonald
<fammacd=!SPAM^nothanks@tellurian.com> wrote:

 >On Sun, 24 Oct 2004 11:19:08 -0400, TheKeith <no.DeleteThis@spam.com> wrote:
 >
  >>I'm building a new computer based on the Intel 915g chipset and the
  >>motherboard I chose (http://tinyurl.com/5s4pk) requires DDR2 memory. I'm
  >>a bit confused about how to purchase memory since the last computer I
  >>built uses SDRAM. Does this stuff have to be bought in pairs for some
  >>reason? I noticed on newegg, you have the option of purchasing single
  >>mem modules or modules in pairs. I can only imagine that the reason they
  >>sell them in pairs like that is because that's the way it has to be
  >>installed? Is this true--could someone please explain? Thanks.
 >
 >If you're confused with the memory choice, which others seem to have sorted
 >out, you may also need to be aware of the need for the latest ATX12V V2.0
 >power supply with a 24-pin main power connector to the mbrd... apparently
 >to do with the new Prescott and PCI Express power reqts. I see very little
 >about this at NewEgg and from what I can see most cases still come with
 >ATX12V V1.x P/S. There are 20-24-pin adapters available but I've no idea
 >how compatible that makes the system. Just another little niggle to bother
 >us all.

Oops, I later found this: <a style='text-decoration: underline;' href="http://www.antec.com/pdf/article/ATX12v2.html" target="_blank">http://www.antec.com/pdf/article/ATX12v2.html</a>
where it states that Intel has, for one of thei rmbrds, officially blessed
sticking a 20-pin connector into a 24-pin mbrd socket... if you can figure
out which is the umm, "rightmost pins".

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: DDR2 memory---must it be bought in pairs? 

 >
 > If you're confused with the memory choice, which others seem to have sorted
 > out, you may also need to be aware of the need for the latest ATX12V V2.0
 > power supply with a 24-pin main power connector to the mbrd... apparently
 > to do with the new Prescott and PCI Express power reqts. I see very little
 > about this at NewEgg and from what I can see most cases still come with
 > ATX12V V1.x P/S. There are 20-24-pin adapters available but I've no idea
 > how compatible that makes the system. Just another little niggle to bother
 > us all.

Wow--I knew nothing about this--thanks for the info. I guess I'll have
to do some shopping around for a decent power supply then. Any
suggestions? The specs of the pc will be:

- foxconn 915G microatx motherboard
- 512x2 DDR2 Corsair valueram
- p4 3.2GHz LGA775
- leadtek gforce 6600 pci-express x16
250GB western digital SATA hd
plextor dvd burner<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: DDR2 memory---must it be bought in pairs? 

actually this is a whole new discussion, so let me create a new post
 >> Stay informed about: DDR2 memory---must it be bought in pairs?