# [SOLVED] Can I use the wrong type of RAM in my laptop?



## gumbyy (Mar 11, 2009)

According to my Google searches, my emachines D520 laptop takes the following type of RAM:

PC2-5300 667MHz DDR2 200 pin SDRAM sodimm

However, where I live, merchants are telling me that this type of RAM is not available anymore. I know you can get in the US on the internet, but I live in a foreign country and it's too expensive to import it.

Computer shops here are telling me that I can substitute this type of RAM:

PC-6400 800MHz

...and it will work fine in my laptop. Is this true? I have one slot now that has 1 GB PC2-5300 667MHz and one empty slot where I want to put the new RAM.

Thanks for any help.


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## gcavan (Aug 13, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

It is true. Your comp will automatically down clock the faster DIMM.


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## GZ (Jan 31, 2010)

*Re: Can I use the wrong type of RAM in my laptop?*

Hello gumbyy,

You should be fine with PC2-6400. 

I would suggest you purchase a matched pair. Mixing RAM of different speeds can cause issues.


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## Tyree (May 10, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

Memory standard for your laptop is- Up to 2 GB of DDR2 667 MHz memory
Upgradeable to 4 GB using two SO-DIMM modules.
How many shops have told you that 667 RAM is no longer available? 
To be certain about the 6400 you could contact the laptop manufacturer.


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## joeten (Dec 4, 2008)

*Re: Can I use the wrong type of RAM in my laptop?*

Which country are you in there may be somewhere online in your area to purchase DDR2 667MHz


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## Rich-M (May 2, 2007)

*Re: Can I use the wrong type of RAM in my laptop?*

If the laptop calls for 667 then that would be the best to run in it though 800 will downsize as suggested. 667 ram should be as plentiful as 800 ram though, something is wrong with what they are telling you or their shops are simply not well stocked. RAM Memory Upgrade: Dell, Mac, Apple, HP, Compaq. USB drives, SSD at Crucial.com should be buyable all over the world and is amongst the best ram you can buy anyway.


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## gumbyy (Mar 11, 2009)

thanks for the replies. I'm in SE Asia and computer shops are definitely not well stocked with memory, they just have a handful of choices. I did find one shop that had 667 but it was second hand and price not much less than a new 800. About buying a matched set to avoid problems, well, but that would mean tossing out my existing 667 which is a waste of money, unless I can get a good price selling it which is doubtful.

Is it likely that I'll have no problems if I install the PC-6400 800MHz alongside my existing 667? If there are problems, I could always buy a second 800MHz later. Unless this mismatch could damage my machine permanently?



gavinzach said:


> Hello gumbyy,
> 
> You should be fine with PC2-6400.
> 
> I would suggest you purchase a matched pair. Mixing RAM of different speeds can cause issues.


The 6400 Ram I've seen here is labeled "PC-6400" not "PC2-6400." Is there a difference?

EDIT: Never mind. I just googled it and discovered there's no difference.

If I did toss my 667 and install two 800s, would my machine be able to run the memory at 800MHz, or is my laptop's motherboard limited to 667MHz of RAM speed? Is there a noticeable difference between the two speeds for most apps?


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## GZ (Jan 31, 2010)

*Re: Can I use the wrong type of RAM in my laptop?*

The machine will still downclock the RAM, but the difference in speeds (likely voltages and timings as well) can cause system instability and unforseen issues. It is always best to have matched DIMMs.


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## Rich-M (May 2, 2007)

*Re: Can I use the wrong type of RAM in my laptop?*

Mixing different ram for speed and model and brand, gives the highest likelihood of incompatibility.


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## Tyree (May 10, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

I would also suggest trying Crucial's site. Crucial is the best option for OEM/standrad use and has a very high likelihood of compatibility.


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## joeten (Dec 4, 2008)

*Re: Can I use the wrong type of RAM in my laptop?*

I would take the advice here as being in your best interest crucial is your best answer


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## gumbyy (Mar 11, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

Thanks again. I'll see if i can trade in my 667 and get 2 800s. I can't mail order Crucial memory, the shipping and import taxes would make it ridiculously expensive.


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## gumbyy (Mar 11, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

By the way, the System Information for Windows utility tells me that my existing 667 memory is running at only 333 MHz. Why is that?


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## gcavan (Aug 13, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

333 MHz is the clock speed. DDR memory cycles on the rising and falling sides of each clock cycle to give a memory speed of 666 MHz Thus its name; *D*ouble *D*ata *R*ate.


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## gumbyy (Mar 11, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

Okay. Thanks for explaining.


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## gumbyy (Mar 11, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

Can I install a 2 GB module instead of a 1 GB? I read somewhere that if you have two slots you should install the same capacity RAM in each one. So since I have 1 GB in one slot, I shouldn't try to put a 2 GB module in the other slot to bring total to 3 GB?


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## gcavan (Aug 13, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

No reason why you cannot. 

For best results both DIMM's should be identical, but it is not mandatory. What will most likely happen, Windows will accept and use all 3GB but only the 1GB DIMM and the first 1GB of the 2GB DIMM will operate in dual channel mode. You may take a slight (probably not noticeable) hit in memory access time over what it would be if 2 x 2GB were used.


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## gumbyy (Mar 11, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*



gcavan said:


> No reason why you cannot.
> 
> For best results both DIMM's should be identical, but it is not mandatory. What will most likely happen, Windows will accept and use all 3GB but only the 1GB DIMM and the first 1GB of the 2GB DIMM will operate in dual channel mode. You may take a slight (probably not noticeable) hit in memory access time over what it would be if 2 x 2GB were used.


Thanks gcavan. Well I am running XP and I don't know anything about dual channel mode or other RAM technical stuff. If I install a 2 GB module in there, to bring the total to 3 GB, will I get the performance benefit of the third GB or not? If not, there's no reason to spend the extra money on a 2 GB module and I will just buy a 1 GB.


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## Rich-M (May 2, 2007)

*Re: Can I use the wrong type of RAM in my laptop?*

Yes you will see a difference and it will be worth it. Dual channel will give you better performance using the same exact ram in 2 slots, but 3 gb will give your more responsiveness than 2 used that way.


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## gumbyy (Mar 11, 2009)

*Re: Can I use the wrong type of RAM in my laptop?*

Thanks, Rich-M


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## Rich-M (May 2, 2007)

*Re: Can I use the wrong type of RAM in my laptop?*

Welcome.


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