Generally, Is it bad to combine two 1 GB DDR2 memory with different densities (chipset varies)

Hello Everyone,

(laptop specs: Presario CQ40-107AU – AMD Athlon 64 X2, ATI RADEON HD 3200 ,1024MB DDR2 SDRAM (1 Dimm))

I bought an additional RAM to upgrade my laptop’s memory from an authorized distributor of Transcend RAMs. They gave me a Transcend branded memory with 1GB DDR2 SO-DIMM CL5 specs (503808-0035 RoHS [NT]). When I was manually installing the memory to the laptop, I noticed that the laptop’s original memory has 8 chips (4 front chips + 4 rear chips) while the memory I bought has 16 chips (8 chips at the back + 8 in front). It worked perfectly after the installation but after 3-4 days, the screen flickered intermittently (3/4 area of the screen at most) while in DOS and in WINDOWS. I’m not sure at this point if this is related to the additional memory I installed or this is an isolated case (video card problem?). Is it bad to combine two 1 GB DDR2 memory with different densities? Both memories are manufactured by Transcend by the way. Or the issue on flickering screen is an isolated case and a factory defect? The shop where I bought the laptop already replaced the laptop and im not sure now if it is safe to reinstall the additional RAM I bought.

 

please help anyone thanks...

 

As long as both memory modules have same latencies you should be ok. Just for sure I would make a bootable Memtest86+ CD (the latest version is 2.01) and test the memory modules.

 

Thanks for your quick response.. so the reason why my screen flickered should be an isolated case right? how do i make a bootable Memtest86+ CD and what is it for? I can measure my new and old memory latency using that software?

thanks thanks

 

Memtest86 carefully checks the RAM looking for any bad bits. It takes some time, so leave it running over night.

Does the computer have an AMD chipset? In my experience they can be fussier about RAM than the Intel chipsets, but if it boots then it should work OK.

John

 

Hi John,
Thanks.Is it compatible with Win Vista Ultimate 64?Would you know where can i find that software?
Im not sure if its using an AMD chipset but its processor is AMD Athlon 64 X2..
Jesse

 

Get the Memtest86 ISO image and use it to make a bootable CD.

Which operating system doesn't matter. If you have a Ubuntu Linux live CD then Memtest86 is also there as a boot option.

John

 

that is very strange, the memory densities are different, but you should still be able to use the memory.
It almost sounds like the memory is not properly grounded, resulting in the screen flickering.
It may also be a big coincidence.
RUn memtest for a good 8-10 hours and see what it comes up with.
If it says everything is fine, than take out the new card you bought and see if the problem occurs again. if the problem stops, you know its somehow related to the new memory card. If the problem continues, than it may just be the lcd connection on the back of your screen.

K-TRON

 

thanks all for your advices.I will try to do memtest run after i install the ram i bought before.

 

Intel Flex Memory - Different density, different timings, different CLs, different frequencies, all will work, and in some cases DC is supported as well.

Controllers prior to the 940GML caused issues, new ones are more forgiving and are able to run completely different memory modules.

 

one more question.. my laptop worked for 4 days after i installed the new RAM. Will it take that long to see that the memory is not safe for my unit?
thakns guys.

 

It is very strange that the problem just started after 4 days.
I think that this may just be a software issue.
Have you tried reinstalling the chipset drivers?

Also did you try running the system with one memory card at a time, like I mentioned in my last post?
The results from running one memory card at a time, could help narrow down the problem. Ie, if the problem appeard when using only one memory card, than that is the solution.

K-TRON

 

thanks k-tron for your quick response.yes, I installed the memory before i installed OS (clean install), drivers etc.. Right now, i have a new unit and have not tried yet installing the new additional RAM I bought as im afraid it may again damage the laptop...

 

well if your warranty still covers, i guess its worth a try? but perhaps the problem is isolated to your old com..

 

If it runs completelty stable with the original ram, than I would think that all of the problems are relating to the other memory card.

I think your problem is occuring because of your ati hybrid graphics card. The 3200 will share the onboard memory, so I am guessing it is very picky.
You may want to return the memory card you bought, and buy the exact same memory card, as the one which came with your system.

K-TRON

 

Thanks for all your comments.. Last week, the shop where i bought the new/addtl RAM replaced the ram (same unit and item) just to make sure that their memory will not affect my new laptop. I installed it also last sunday and its still working until now w/o problems. Meaning, it is okay for high and low density mixed up for my laptops mobo...thanks again