EDO DIMM pin and notch layout same as SDRAM DIMM? -Solved, answer is inside if interested

[brinstar117]

Argh, usually I know these things. I have two sticks of EDO DIMMs in front of me. They are 168 pin. The contacts line up the same way as a 168 pin SDRAM DIMM, however the notch inbetween the the 20 pin and 60 pin groups isn't lined up with the corresponding notch on an SDRAM DIMM. It's about 2mm farther away from the 20 pin group than on an SDRAM DIMM.

This is normal, right? Probably... my mind is fuzzy right now Unfortunately I have no motherboards that accept EDO DIMMs at this moment to test it out on. I have an Asus P2L97 board that says it can accept EDO DIMMs but the sticks won't fit in the slots.

EDIT:

Found out the reason finally, the EDO DIMMs I have are buffered, thus the notch between the 10 and 11 pin is centered.

Whereas in a non-buffered DIMM the notch is closer to the 10 pin.

The motherboard I tested it in only accepts non-buffered EDO DIMMs or SDRAM DIMMs.

I used these DIMMs in a Pentium Pro motherboard and they work flawlessly

 

[numark]

I would guess that's just some sort of keying. After all, SDRAM sockets won't accept EDO DIMMs even if you could fit them, the speed would be just too slow. In other words, perfectly normal

 

[brinstar117]

Manual for my Pentium 2 Mobo, ram support on page 17 It says it accepts EDO DIMMs on page 17.

Specifications for my RAM (pdf file)
My ram stick part number is: MT36LD3272G-5 X

A dimensions layout is on the 2nd from the last page. It is the module on the top of the 2nd from the last page.


Pic of my EDO DIMM (not my auction)

I know that my motherboard won't accept this type of ram (module is too large in capacity and I don't think it supports buffered RAM). However, the module should at least fit into the ram slots right? The key for EDO DIMMs should be the same regardless if they're buffered/non-buffered, parity/non-parity, ECC/non-ECC, or any size capacity right?

Thanks!

 

[AndyHui]

Don't bother. EDO DIMMs require 5 volts. The regular SDRAM DIMMs that we use today are 3.3 volts.

That's your problem....the voltage key on the EDO DIMM is not allowing you to insert it.

 

[brinstar117]

Thanks for the reply FAQ man, however according to the specification sheet, my EDO DIMMs are 3.3 volt.

 

[bozo1]

There are EDO SDRAM DIMMs out there but it is not commonly used. Compaq used them in some of their servers a few years ago.

 

[TwilightZone77]

I have an old Pentium that accepts either EDO or SDRAM DIMMs, using the same slots.

 

[brinstar117]

Found out the reason finally, the EDO DIMMs I have are buffered, thus the notch between the 10 and 11 pin is centered.

Whereas in a non-buffered DIMM the notch is closer to the 10 pin.

The motherboard I tested it in only accepts non-buffered EDO DIMMs or SDRAM DIMMs.

I used these DIMMs in a Pentium Pro motherboard and they work flawlessly

 

[Blackbandit]

yes the one notch you are refereing to is to detemine buffered/non buffered and the other slot to the right detemines the voltage. Same theory, the slot is either centered or a little off center. you should be using EDO 3.3v Dimms. 5.5v were mostly used for Mac systems