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Mix different speed RAM. Possible?

Last response: in Memory
January 6, 2010 9:53:15 AM

I have two RAM modules.
Both are 1GB.
Different speed ratings.
One is 800Mhz.
Other is 667Mhz.

1GB PC2-6400 DDR2-800MHz

1GB PC2-5300 DDR2 667MHz

I have 4 slots
2 black, 2 blue.
Paired as opposites, i.e. blackblue blackblue.

I have tried various combinations, but it hasn't worked.

One beep, 3 quick beeps, 3 quick beeps, one beep.
This repeats itself.

If I only put any one 1GB in any slot, it works fine.
I'd like to have 2GB, if possible.

I'm thinking it's something to do with the BIOS, but I looked and there's no RAM options there.

CPU-Z says my motherboard is
Fujitsu Siemens

Chipset Intel E7230
Southbridge Intel 82801GB (ICH7/R)

Processor Intel Pentium D 945 Socket 775 LGA 3.40Ghz
Fujitsu Siemens // Phoenix Technologies Ltd.
Version 4.06 R1.04.2179.R1
Date 09/28/2006

I've looked for an updated BIOS, but I can't find one.

Any ideas?

More about : mix speed ram

January 6, 2010 11:00:24 AM

Its possible but highly not recommended....Buy/Use exactly the same memory module. Its an invitation to problem or issues.

If you have to set your ram speed to slower setting 667 for it to have a better chance of working. It is still not recommended.
January 6, 2010 11:04:10 AM

It should automatically set both to 667 in that case, but like leon said, you should really just get two of the same types of RAM. Timing differences can cause issues.
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a b } Memory
January 6, 2010 11:28:34 AM

You'll have to run the 800 CAS6 timings and set them manually, that is, if the M/B allows setting the timings manually in the first place, but as has already been said, its not really a good idea to mix modules with that much of a difference.

It either won't work period or be a serious performance killer, it all really depends on what your M/B will allow you to do, some automatically set the timings leaving you no options.
a c 81 } Memory
January 6, 2010 11:33:58 AM

Since that motherboard uses an Intel E7230 chipset, it probably is a server or workstation motherboard that doesn't provide manual settings.
January 6, 2010 1:24:01 PM

The model is fujitsu siemens primergy econel 100.

The RAM that came with it is the 667Mhz.
I lifted the other 800Mhz one from a dead machine.

I've looked at the BIOS settings, there are no RAM settings/options.

It's just weird that it can use either one, but not both.

But as you said, with Intel E7230 chipset, it doesn't let me configure. So probably that's why it can only use one speed and not a combo of speeds.

Cheers guys, I'll stick with the RAM that's in there already.