Talk:SO-DIMM

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Contents 1 Compatibility with different types of memory 2 We are no longer in the days of non-DDR SDRAM 3 DDR/DDR2 4 pictures 5 correction 6 DDR and DDR2 pictures - notches 7 all about the life ( in french )

[edit] Compatibility with different types of memory

There is a new version, ddr2 sodimm. I bought it for a ddr sodimm laptop and it is incompatible. Maybe some information should be added. (-someone)

Agreed. There should be info on what type of memory is supported. I.E: a 266mhz is backward compatible with 133mhz but other are not... is that the case?

DDR or DDR2 are not backward compatible with other kinds. PC133 is not compatible with Intel 440xx and 810 chipset using PC100. (-someone)

Usually the situation is more complex. Usually within a type, the faster modules are SOMETIMES backwards compatible. Often the problem is with "chip density" -- when the module is faster AND built with denser chips, maybe for greater total capacity, then it may not work in older slots designed earlier. 69.87.193.203 21:41, 26 November 2006 (UTC)

[edit] We are no longer in the days of non-DDR SDRAM

Why does it talk about "regular" 168-pin RAM? Nowadays the norm is 184- or 240-pin memory. Geekosaurus

[edit] DDR/DDR2

I demand information on DDR and DDR2 SODIMMs!--66.3.224.199 21:00, 7 October 2006 (UTC)

At Nov. 27, 2006 my friend and I were attempting to use the SO-DIMM wikipedia page to verify the type of ram he had purchased. The labelling of the ram he had purchased, the labelling of the ram he had installed, and the wikipedia page did not correspond. After some research, I have determined that the key notch for DDR2 belongs towards the center of the ram board, while DDR goes towards the outside. For reference, see Jedec document section 4.20.6 for SO-DIMM DDR voltage specs, Jedec document section 4.20.11 for DDR2 voltage specs, and Jedec document MO-224 for schematic layouts of the physical boards. Note that as per Jedec section 4.20.6, that DDR is 2.5-2.7V, with the left key (outwards) used and right key reserved. Jedec section 4.20.11 has DDR2 at 1.8V, with the right (inwards) key used and the left key reserved. Document MO-224 does not reference common names (DDR vs. DDR2), but does confirm the position based on voltage. I have corrected the page as such, and hopefully someone more knowelegable can verify. Macavity 01:02, 28 November 2006 (UTC)

[edit] pictures

We need pictures of each type, with a ruler and at the same scale, so people see the notches etc. 69.87.193.203 21:37, 26 November 2006 (UTC)

[edit] correction

The different types of SO-DIMMs can be recognized at a glance by the distinctive notches used to "key" them for different applications: 100-pin SO-DIMMs have two notches, 144-pin SO-DIMMs have a single notch near (but not at) the center, and 200-pin SO-DIMMs have a single notch nearer to one side.

This is to a degree incorrect, I have a 16mb RAM stick in a Digital Hi-Note VP and a 64mb stick in a Toshiba Tecra 8000, the sticks ARE NOT compatable even though they both have 1 notch, they are about 1mm from aligning with each other. It is a possiblity that Digital used propriatry RAM but I have no idea as the laptop is probbably older than I am, and it was given to me freely without any manual etc :(

[edit] DDR and DDR2 pictures - notches

As of 11/19, regarding the two pictures used to illustrate the distinguishing different notch locations for DDR and DDR2 memory. The article says the notch is closer to the center for the DDR2 memory. In the pictures don't the notches appear to be in the same location relative to the sides of the memory? If the DDR2 memory picture really is of DDR2 memory then there actually isn't much difference in notch location.

Gloryroad (talk) 17:08, 18 November 2007 (UTC)

I cropped and resized the existing photos of DDR and DDR2 and compared them closely, edge to edge. There is a very-very-very small difference between the two notch locations, much less then I'ld have expected in my ignorance of DDR2. Plus the DDR2 seems to have 19 contacts, versus DDR's 20, on the short side of the notch. One wonders why the designer(s) would bother changing the notch location, seemingly to distinguish the two, and then not make the difference large enough to be immediately apparent. If 19 contacts to the side of the notch is consistent with DDR2, perhaps that is a better indicator.

If this is all correct, it might be helpful if the article emphasized that the notch difference is minute (not just slight) and requires careful observation to distinguish.

Gloryroad (talk) 14:05, 22 November 2007 (UTC)

[edit] all about the life ( in french )

bonjour je me nomme m_ _ _ _ _ _ je suis tres special car c MOI qui a fait cela hhaha bye —Preceding unsigned comment added by Marilou.cuty (talk • contribs) 23:11, 11 April 2008 (UTC)