DDR2 667 and 800, can they be used together ?

Hi,

I have two noebooks, one using DDR2 800 another older one using 667. I have upgraded the 800 one from 4G -> 6G and tried to move the 2G DDR2-800 to the 667(which has 2.5G). Both are running very stable before the change.

However, it seems that the 667 + 800 is not very stable.

First, the BIOS is supposed to only do one RAM check(count or whatever it is) when there is configuration changes. With this setup, now it do it on every reboot.

Second, the machine may not be able to resume from sleep and randomly BSOD.

Is there any way I can fix it ?

thanks.

 

Normally they should work without an issue. BIOS automatically sets the speed to the slowest one. So the DDR2 800 stick should be running at DDR2 667.

However since you are getting BSODs I would suspect that one of the RAMs might be broken. Run the memtest program and see if it gives any errors.


--

 

This is why I always suggest to get identical RAM modules, but to try to help you with your specific issues:

Did you try to switch the slots the modules are in?

This may force the chipset to stick to the slower RAM and be more stable for you.

Make sure you unplug the power and remove the battery before you remove the RAM.

Good luck.

 

Yes, try everything including running the memory test.

To complicate the matter, the CPU is supposed to be running @ 533 FSB and it is one of those AMD integrated GPU(that takes RAM from OS).

If I just use any one of them, they worked fine, putting two together it ranges from failed to POST on reboot, failed to resume from sleep or BSOD after resume.

I give up on it and revert back to my old 2.5G configuration, it is only 700MB anyway.

thanks for the suggestions and yes despite that technically they are supposed to be adjusting themselves, it seems that is not the case and depends on a lot of things.

 

Hmmm... too bad you couldn't get it to work - but at least your symptoms were evident right away.

I've had clients systems who had put together a system from two or three older ones and couldn't quite track down why this 'frankensystem' wasn't stable - simply installing identical RAM modules solved their little glitches - but boy was it hard to get them to buy the identical RAM in the first place.

I would buy two identical modules for your machine and sell your current RAM sticks - 700MB RAM does make a difference!

Good luck.

 

this one is a bit long in the tooth so I don't want to shell out any extra $ on it(other than upgraded the HDD to Scorpio Black) as buying new stuff means shipping + tax which no way I can recoup from the old stuff on craigslist.

It would be retired in 2012 when I am planning to get a new Ivy Bridge anyway.

And that 700MB didn't make a noticeable difference in usage that I have tried for the past month or so. As I only use this machine for casual things so it is just more cache for the OS most of the time.

But still appreciate the suggestions of getting two identical modules, would definitely do that in the future given what I have experienced.

 

Okay, for light use, then 700MB extra is not really necessary, I agree.

What I would be interested in though is trying the (more matched) 800MHz modules (from your other system) on this system to see that it is stable at all.

No reason - Just curious.

It would let you know if the module timing differences were to blame though (it might be your actual RAM slots on this computer, for example?).

 

yes, that is what I want to do, but that module is 5000 miles away from me and I won't be seeing it until end of this year

it is a machine I bought for my family(parents and nephew), I am the only one who would deal with computer matters in my family

And just in case, even my current 2.5G setup is not using modules of the same timing. 512MB of the original 533, 2GB of 667. Which was why I initially thought that there should be no problem.

 

If I'm not mistaken, the physical construction of 533/667 modules is closer than 667/800 modules - maybe this is why the 667/800 combo doesn't work?

 

no idea and cannot test anything else at the moment other than knowing 667 + 800 on this particular machine doesn't work :-(

It really is a 'frankensystem' as the CPU is @ 533 FSB, the ATI/AMD 1250 is supposed to take portion of the RAM as dedicated video RAM(not sure about its timing) and throwing in the 667 +800 mix may mean too much for it and the BIOS is pretty old too.