Memory Compatibility

Hi hi.

I have 1GB x2 of DDR2-1066 memory, but I don't want to dish out the extra money to get other 1066MHz modules. Can I underclock 1066MHz modules to get them to work with DDR2-800 memory?

Thanks in advance.

Odd - but anyway...

Correct me if I'm wrong, fellow techs, but all installed memory will run at the speed of the slowest installed module without any tweaks, right?

Not sure if it will cause any spurious errors though.

I've posted on other forums and they've told me this too. I'll go for it then, thanks.

It won`t hurt to try it. But there are a few things to be aware of.

- Some systems will set themselves to run at the speed of the slowest RAM, but some will only read the info off the first RAM module and set things to that. In that case, you'd want the DDR2-800 modules to be first (usually, the lowest numbered RAM slots). You might also need to get into the BIOS and manually set the RAM timings.

- RAM is not always under-clockable. It depends upon the range of timings in the particular modules. One way to find out is to get into the BIOS and, if possible, manually set the RAM to DDR2-800 and see if it works.

well it should work, I believe that most Bios will allow you to underclock the ram if you need to. Jus plug them in and give it a go, the worst thing is that it won't boot and you will have to tweak it manually for the second boot up.

Alright!

What about using DDR2-1066 RAM for motherboards that support only up to DDR2-800? Would that 1066 RAM be clocked down to 800 or would it not work at all? =S

As long as it's DDR2, it should be fine.

Anyone else confirm?

The RAM modules will auto tune to run at the speed of the lowest modules. You may have to manually adjust the faster modules to have tighter timings, equivalent to that of the slower modules. This can be done through the BIOS under memory settings. Just look up the timings for your DDR800 modules, and adjust the timings to match that. Make sure the voltage is set to run at the DDR800 level, not the DDR1066 level. That will ensure maximum stability. Again, you will not be able to enable dual channel mode though.

K, going to get some cheapo modules this weekend so I can get over 2GB of memory. When I play Company of Heroes: Opposing Fronts (DX10) or Crysis Warhead (DX10), my memory usage hits the roof at 99% and my FPS gets minimal.

Eh, somebody told me that my DDR2-1066 modules are running at only 533MHz because of my stock-clocked Core 2 Duo E7200. Is that true? 0.o This is what he told me: