Adding RAM with different clock speed(bad idea?)

[jasong]

I have a 2.8GHz dual-core Pentium-D with 2x512MB of DDR2 RAM at 266MHz that I got as a gift from my father. My father offered me a stick of 512MB of 400MHz DDR-RAM.

Is it a bad idea to combine them? I don't have a lot of money, and another 512MB of RAM would allow me to participate in the main effort of the Odd Perfect Number search, which is the whole reason I wanted the extra RAM in the first place.

So, should I use the RAM? Should I totally replace my RAM? What should I do?

[paulunderwood]

In theory the DDR400 will run at 133MHz (DDR266) if combined with DDR266. However, I have had problems booting a machine with mixed DDR frequencies.

Did you mean mixing DDR2 with DDR?

You might find you get more throughput using only the DDR266 in "dual channel" mode.

I have also have had problems mixing CL2 with CL2.5 memory

[xilman]

Originally Posted by jasong

I have a 2.8GHz dual-core Pentium-D with 2x512MB of DDR2 RAM at 266MHz that I got as a gift from my father. My father offered me a stick of 512MB of 400MHz DDR-RAM.

Is it a bad idea to combine them? I don't have a lot of money, and another 512MB of RAM would allow me to participate in the main effort of the Odd Perfect Number search, which is the whole reason I wanted the extra RAM in the first place.

So, should I use the RAM? Should I totally replace my RAM? What should I do?

I suggest that you try to borrow the extra RAM and see if it works in your system. If so, pay your father the agreed price, otherwise return it.

Paul

[jasong]

Originally Posted by xilman

I suggest that you try to borrow the extra RAM and see if it works in your system. If so, pay your father the agreed price, otherwise return it.

Paul

It would've been free RAM if I had taken it. :) As it turns out, something must be screwy with cpu-z, because my dad says it's 533MHz RAM. He tried to put in the extra stick, but discovered(sorry, I don't know the lingo here) that the slots didn't line up, so, unless I get a different case, I will NEVER be able to use the RAM he offered. But, since he has a different type of case, he now has 1.5Gig of RAM in his own system.

[moo]

ddr2 and ddr are seperate technologies
ddr and ddr2 use different slots to minimize confusion just like most procs use different slots
if you even had any thoughts of putting ddr in a ddr2 system drop them you would run the risk of distroying your board and other parts of the system.
ddr2 is also faster the then fastest ddr sticks higher clock and what not. so if it did work your memory clock would drop to 400 from 533

[E_tron]

I ran this mix in my machine before i upgraded:

channel 1:
512MB DDR 400
channel 2:
256MB DDR 266
128MB DDR 266 ECC

the entire setup ran at DDR266.

See if you can get rid of the slower memory, because it does make a difference.

Note: you cannot mix different memory technologies, so DDR and DDR2 will not play together.

[Andi47]

Originally Posted by E_tron

I ran this mix in my machine before i upgraded:

channel 1:
512MB DDR 400
channel 2:
256MB DDR 266
128MB DDR 266 ECC

the entire setup ran at DDR266.

See if you can get rid of the slower memory, because it does make a difference.

Note: you cannot mix different memory technologies, so DDR and DDR2 will not play together.

Despite the difference in speed - would there be an elevated risk of crashing or errors if I used RAM with different speeds (e.g. 2*1024 GB DDR2 533 and 2*1024 GB DDR2 600)?

I have this system that needs more RAM - but I have no use for the old RAM - I have been told that RAM works best in even pairs. But I have seen machines that just fill up the slots with speed matched RAM and it works fine. This was ofcourse with SD RAM

I know RD RAM is always installed in pairs (Yes I use RD RAM - it's a olded system that works great.)

What about DDR RAM and DDR2 RAM - can you put a 512 MB and 256 MB Stick together and not have errors ??

Current these systems are utilizing single sticks and there is free slots for at least one other stick.

[Cruelty]

Originally Posted by Unregistered

What about DDR RAM and DDR2 RAM - can you put a 512 MB and 256 MB Stick together and not have errors ??

It might be possible in single-channel mode.
IMO: in dual-channel, at least each channel should have the same memory installed. Anyways, if you encounter any problems or errors on such configuration, this will be a clear indication that memory subsytem is not functioning properly. You may also consult motherboard manual to see what RAM configurations are allowed.
In single-channel mode you may increase system stability by manually increasing the memory timings, eg. Cas Latency, Command Rate etc. - however timings should be the same for all RAMs installed.