Which memory can I use?

[maan84]

Hello!

I am thinking about upgrading my RAM, my mother board is Intel® Desktop Board D915PCY and it supports DDR2 533 MHz and DDR2 400 MHz DIMMs according to http://www.intel.com/products/motherboard/d915pcy/index.htm

Right now I have 512MB of ram, and it is
Corsair CM2X512-5400C4 XMS2-5400 512Mb DDR2 PC5400 4-4-4-12 667MHz with Heatsink.

Though notice that these are 667MHz, and my motherboard support up to 533MHz, so according to my bios they run at 533MHz, and cpu-z says Frequency: 266,7MHz on the memory tab and on the SPD tab it says Frequency 333 MHz also the same on Max Bandwidht, I personally don't know what this means and why they differ from what the bios tells me? That is one question Thank you for taking your time.

And my other is, I plan to buy another 512 or 1024 MB of RAM, but probably 512, does this memory have to be 667MHz also, or will 533MHz be ok since they run at that speed and it is what my mobo support?

Thanks again!

 

[Matthias99]

Originally posted by: maan84
Though notice that these are 667MHz, and my motherboard support up to 533MHz, so according to my bios they run at 533MHz, and cpu-z says Frequency: 266,7MHz on the memory tab and on the SPD tab it says Frequency 333 MHz also the same on Max Bandwidht, I personally don't know what this means and why they differ from what the bios tells me? That is one question Thank you for taking your time.

Your system is reporting everything correctly. You have DDR2-667 RAM (which runs at 333Mhz), but you are running it at DDR2-533 speed (ie, 266Mhz). The SPD tab is reporting the default settings built into the RAM, but your BIOS is overriding those and making it run slower. Dual Data Rate (DDR) RAM transfers data twice per clock, which is why sometimes you see the "real" speed listed as half of the rated speed.

And my other is, I plan to buy another 512 or 1024 MB of RAM, but probably 512, does this memory have to 667MHz also, or will 533MHz be ok since they run at that speed and it is what my mobo support?

Thanks again!

You can use any* DDR2-533 or DDR2-667 RAM. It will just run at 533Mhz.

*To run in dual-channel mode, you will need RAM that can run the same timings as your current RAM (or you will have to run at the slower timings that the new chip can support).

 

[maan84]

Ah now I see, should have been able to figure that out I guess

Thank you for your answer!