DDR RAM in a DDR2 slot?

Hi! I have a very old Toshiba Satellite L20 that I'm making do with until the Sandy Bridge situation gets settled. It only has 512MB of RAM (2x256) and really slow, so I decided to replace one or both of the RAM sticks with 1GB pieces.

The problem is I don't know which RAM sticks to use. It has 2 DDR RAM sticks in it. But the crucial memory scanner advises to get 2x1G DDR2 SODIMM, eventhough it's showing 2x256MB DRR SODIMM present. I don't know what memory the laptop came with as I got this laptop from my brother who got it from my other brother; I'm not sure if someone "upgraded" the memory from DDR2 (64? 128?) to DDR 256 (maybe DDR was cheaper back then). The sticks now are definitely not stock, as they're 2 different brands.

Googling Toshiba Satellite L20 RAM doesn't help either, as some sites are showing DDR while others DDR2. I know you can't interchange DDR and DDR2 memory, but is it possible that I've been running with DDR memory in a DDR2 slot all this time? Everyone's saying DDR2 in a DDR slot won't work, but can a DDR work on a DDR2 slot. It's (stick) rated 2.5V but just getting a lower 1.8V (slot)

 

CPU-Z your laptop chipset and find out officially what RAM it supports.

 

DDR and DDR2 are completely incompatible in any way. You either have DDR or DDR2, and never the option to use the other. It may be the case that the Toshiba L20 was offered in DDR and then in DDR2. You just need to use CPU-Z like tsunami kid mentioned to see for sure which one you have.

 

Do'h! Of course, CPU-Z.


According to CPU-Z, it's DDR2. I physically checked the RAM sticks, and they're clearly marked DDR. W T F?

Does that mean I can buy DDR2 now? Or do I need to run another diagnostic program?

 

What frequency, timings, and voltage is it saying?

 

Sometimes timings, speed aren't indicative of the specific RAM, especially when DDR2 first came out.

CPU-Z the chipset, then google Intel's Ark site and found out the RAM it officially supports.

 

found this for you. hope it helps

Memory Upgrade for Toshiba Satellite L20 Series Laptop, the Toshiba Satellite L20 Series Laptop takes the PC2-4200 DDR2 SDRAM SODIMMs Memory Type, and comes installed with 256 MB (removable) of Memory. You can upgrade your Toshiba Satellite L20 Series Laptop to up to a maximum of 2.0 GB Memory, the system has 2 sockets to install Memory, already with 256 MB (removable) standard Memory installed. For best Laptop performance use the maximum amount of allowed Memory per slot for your Laptop.
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They don't fit in the same slots. On a laptop, they are both 200 pins, but the notch is in a different place. I've heard of desktop boards made during the transition that supported both (extra slots).. but I don't think anyone ever did that on a laptop

 

The notch is not in a difference place, DDR WILL fit into DDR2 and vice versa (SODIMM modules). But they are totally different RAM, voltages and will not post if the wrong RAM is used. I filmed a video about RAM for my workplace and we showed the RAM looks the same and fits but are totally different.

 

It doesn't fit unless you really jam it in there and probably break something.

 

DDR and DDR2 will fit in the same slot, as stupid as it is.

 

DDR2 SDRAM - Wikipedia, the free encyclopedia
from said link
DDR2 DIMMs are not designed to be backward compatible with DDR DIMMs. The notch on DDR2 DIMMs is in a different position from DDR DIMMs, and the pin density is higher than DDR DIMMs in desktops. DDR2 is a 240-pin module, DDR is a 184-pin module. Notebooks have 200-pin modules for DDR and DDR2, however the notch on DDR modules is in a slightly different position than that on DDR2 modules.

 

Here you go, nearly identical, which means it can probably fit.

File:Laptop SODIMM DDR Memory Comparison V2.svg - Wikimedia Commons



Here is the photo greatly enlarged to read it better.

http://upload.wikimedia.org/wikiped...aptop_SODIMM_DDR_Memory_Comparison_V2.svg.png

But basically 0.1cm difference between the centerlines of the slot. That's 0.04" I hope they built everything to exact tolerances because that's essentially the same to me.

 

It isn't going to fit without breaking something. Just because the notch is close doesn't mean it "fits." A millimeter is much wider than a single pin. You are going to know if you are trying to insert a DDR2 module into a DDR slot and vice versa.

 

Right, understand, but that's +/- 0.5mm. The PCB width itself probably is within that tolerance range. The slot on the RAM chip I just measured is about 1.5mm wide, and the plastic tab is only 0.5mm wide, so that leaves movement side to side of +/- 0.5mm, so there's easily possibility to fit a DDR in a DDR2. I will look to see if I have an old DDR SODIMM and fit it in a DDR2 laptop. I'm just curious now.

 

because of the different voltages i cant see it working

 

That's the point, it won't work, but it might fit.

 

Maybe this will illustrate it better?

 

It doesn't matter how much "nearly identical" they are, since they are NOT identical. That "nearly" makes the difference between "it does fit" and "it doesn't fit".

Of course there are always strong enough people that can make things fit together, but it this case you will end up with a non-functional notebook

 

Get out the old file

Not really, don't do it.