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Hi. Thanks for the explanation. I still don't understand what is "dual" about the dim, nor do I understand what is "in line" about it. Is the DIMM "dual" because it carries information on each side of a pin? I am trying to understand what makes a DIMM, different than a SIMM. Thanks for any help you can provide. —Preceding unsigned comment added by (talkcontribs) 0:20 UTC, 14 February 2005

the major difference between simm and dimm is that simm can work on single line that is it can work on one side of the ram whereas dimm which is dual in line memory module can work on both sides of the ram.
sub:varun verma —Preceding unsigned comment added by (talkcontribs) 08:30 UTC, 20 June 2005

hello my name is siby. i whish you include the speed of DIMM used in computer system.

I added an explination of the differences between DIMMs and SIMMs. And I think this article has enough information that we can remove the stub status. Any objections? --Pboyd04 20:42, 26 December 2005 (UTC)

Pin layout[edit]

Does anyone have references for the pin layouts and method of operation of the different types of DIMM? It would certainly be useful to address this topics. JulesH 11:17, 13 October 2006 (UTC)

you 're right. i have inserte the package gorm of 168 pin (13 cm and 2 holes), i'd like to see others version too. -- 17:10, 12 September 2007 (UTC)

ps i was looking for package list and i found this page [1] (sorry this is a commercial site but i haven't found a free site yet) —Preceding unsigned comment added by (talk) 17:16, 12 September 2007 (UTC)

As far as I know DIMM SDRAM memory has 184pinn,and one hole in the center. The 2 holes might be DDR SDRAM. —Preceding unsigned comment added by (talk) 22:21, 27 March 2009 (UTC)

DDR1 and DDR2 Speed[edit]

In the speed section can you clarify the difference between the speeds of DDR1 and DD2... is the strobe at the same speed as the data and twice the clock in both cases? ...

DDR1 ...have data but not the strobe at double the rate of the clock. i.e., PC1600 = 200 MHz data & strobe / 100 MHz clock for address and control .... DDR2 ... also (?) have data and data strobe frequencies at double the rate of the clock. i.e., PC2-3200 = 400 MHz data & strobe / 200 MHz clock for address and control .... Jnwisner 16:45, 14 July 2007 (UTC)

Memory module description in EEPROM chip[edit]

I miss a notice that most DIMM modules carry a small EEPROM chip that describeS specification of the module (capacity, timing, manufacturer, etc). And I miss a detail article about this EEPROM chip, that is accesible at I2C bus on most cases as I know. Information from the chip can be read with Z-CPU freeware under Windows, for example. BIOS process the information from EEPROM chip too to configure system to optimal values during computer boot.

Well, I found the article about SPD: Serial_Presence_Detect —Preceding unsigned comment added by (talk) 11:12, 27 January 2008 (UTC)

Am I wrong or is this whole section plain wrong? There's DIMM SDRAM,and DDR SDRAM; a big difference! It seems they mix it up a bit! DIMM SDRAM = supposed to be 184 pin, one hole on the bottom, 2 holes on the sides, and speeds ranging somewhere like 66 to 100Mhz. (It might be possible that 33Mhz or 133Mhz exists too). DDR speeds usually go higher then 100Mhz. —Preceding unsigned comment added by (talk) 22:24, 27 March 2009 (UTC)


Given that there's no definition of exactly what a MicroDIMM is, in what devices it is used, etc., I have a hard time understanding why MicroDIMM redirects here, other than the fact that the word is on the page. Anyone care to add a description? —Preceding unsigned comment added by (talk) 15:53, 6 March 2008 (UTC)

My laptop has a MicroDimm slot fare as i know its used for more memory all u know at the moment but will keep u informed if i find out much more :) J M F Daddy

Other DIMMs than mainstream?[edit]

What about DIMMs used e.g. in printers, set-top boxes, cisco router, etc. pp.? Not even mentioned here... I don't have any information about them but they occur mostly in powerpc appliances and are equipped with sdrams as well as with normal drams. —Preceding unsigned comment added by (talk) 19:39, 22 June 2009 (UTC)

Yes, other DIMMs[edit]

I worked as atech for Computer City and ran into regular sized 144-pin DIMMs several times. They were basically mirrored 72-pin SIMMs, if you put them into the computer only half the RAM is available. I remember Canon desktop computers used those and the memory slots could interchange 72 and 144 pin variants. There was another brand, I think it was UMAX MAC clone (at that short time that Apple was licensing their OS). Apple had eprom DIMMs for Mac ROMs. Shjacks45 (talk) 20:02, 16 March 2012 (UTC)

Ease of installation comparison[edit]

Add a comparison table of ease of installation, e.g., in

Press gently but firmly until the clamps close completely. You may need to push the clamps in toward the chip, but do so very gently. If the chip does not fit, do not force it.

Perhaps other designs are easier for the user.... Jidanni (talk) 02:16, 17 July 2012 (UTC)

The description for DDR3 and DDR4 is basically the same.[edit]

I'm no expert, but this seems weird. Surely it should be quadruple the clock speed, and not just double? I don't feel certain enough to edit, but if someone else knows anything about it this should at least be clarified. — Preceding unsigned comment added by (talk) 12:22, 25 August 25 2014‎ (UTC)

Hello! Actually, DDR(1), DDR2, DDR3 and DDR4 all perform at double the rate of their clocks. The n in DDRn serves as a generation designation. — Dsimic (talk | contribs) 03:44, 26 August 2014 (UTC)

Registered DIMMs[edit]

The term/concept "registered DIMM" is used and not explained.

"JEDEC decided that the terms "dual-sided," "double-sided," or "dual-banked" were not correct when applied to registered DIMMs." (talk) 08:55, 10 March 2015 (UTC)

Hello! Please see the DIMM § 168-pin SDRAM section above – it contains a link to the Registered memory article, which explains the whole concept. In Wikipedia articles, it is a common practice not to link the same term multiple times, so "registered" isn't linked more than once. — Dsimic (talk | contribs) 10:18, 10 March 2015 (UTC)

Concerning section: 168-pin SDRAM[edit]

I don't know if it's me, but I can only see one notch on the bottom edge...

Also, just to clarify, the notch is the thing that makes it impossible to but it in the wrong way or to put in a module not designed for the slot at all, right? — Preceding unsigned comment added by (talk) 09:06, 10 March 2015 (UTC)

Please make sure you're looking at the right image; File:DIMMs.jpg (which is visible at the top of the article) shows a 168-pin SDRAM DIMM, which clearly has two notches. You're right, the notch is the mechanical characteristic of a DIMM module's edge connector that makes it impossible to mismatch memory types. — Dsimic (talk | contribs) 10:24, 10 March 2015 (UTC)