Windows 7 - Will putting a DDR 2 667 MHz RAM with a 533 MHz cause problems?

I am planning to upgrade my system from 1 GB to 2 GB. Currently I have a DDR 2 533 RAM card of 1 GB. I am planning on putting another 1 GB RAM card, but it's a 667. What are the problems that will come? Can automatic reboots happen?

Also, IF I put a 1 GB 533 MHz RAM card instead of a 667 one, will THAT cause any problems as well?

If in dual channel the slower module speed will be used. But the answer is no, you should have no problem.

But will be best to keep the module speeds the same.!!

Thanks man! But I'm not sure about dual module - what does that mean?

You mean dual channel? Read THIS

Everything You Need to Know About the Dual-, Triple-, and Quad-Channel Memory Architectures | Hardware Secrets

Single and dual channel mode refer to the effective memory bandwidth.

Single Channel Mode: Here, only one stick of RAM is installed. So long as it is supported by your system (and most should be, if they are physically compatible), the stick will work. The effective memory footprint will be 64-bits wide.

Dual Channel Mode: Here, two sticks of RAM are installed. Again, so long as they are supported by your system they should work and provide double the memory footprint, i.e. 128-bits wide. However, it is not necessarily as easy as that. The memory will only operate at the highest common speed, so a module rated at 667MHz coupled with one at 533MHz will run at the slower speed of 533MHz. In addition to that, timing issues play a part. Ideally, the timing values should be identical. For best results, it is recommended that identical modules should be used in such setups.

Will non-identical DDR 2 RAMs cause automatic reboots from time to time?

If both modules work fine you should have no problems..

Thanks man! Both modules working fine means that the system should reboot :-) But what if I play a game like Harry Potter 4? When the screen blackens momentarily before going to the game, or when I'm half-way playing it, will there be a sudden reboot? What are the causes for automatic reboots anyway :-)?

This could be any number of causes, could you please read this and post back with the results so we can have a look for you.... Blue Screen of Death (BSOD) Posting Instructions

Just follow the instructions..