Here are the ram specifics for my com : Maximum allowed = 2gb Speed supported = PC2-4200MB/sec Type = 240 pin. DDR2 SDRAM I wanna know, if i must be only concerned whether it is DDR2, and that the speed supported is not really necessary? Hence, i can get this : 1 GB 800Mhz PC2-6400 DDR2DIMM? Or can i only get this : 1 GB 533Mhz PC2-4200 DDR2 DIMM ? Also pls do tell me the significance of the frequency. Thank you for your support.
easiest and safest thing to do is - check out your motherboards printed/online manual for the supported RAM types/vendors. but overall - frequency matters - if your mobo doesn't support the frequency, the module will not work and might even do physical damage. as an example: my mobo supports DDR2 with a maximum freq of 533 mhz. So, I wouldn't go and buy a DDR2 module w/ 800mhz freq. (both are DDR2, but having different freqs makes the second uncompatible with my system)
That's incorrect. RAM speed ratings are like the speed ratings for tires in that they indicate the maximum. A tire rated for 150MPH will work fine at 40MPH. Likewise PC2-6400 will run fine at slower speeds. If this were wrong, my 2nd box would have been damaged by now. I only need PC2-4200 to be paired with my Pentium D, and I have PC2-5300. Also many people use DDR2 rated way above the specs for the chipset without issue. Where you will run into trouble is if you try to run RAM slower than what the CPU and chipset are made for. Typically, chipsets will support the lowest common denominator, which is why every chipset using DDR will support PC-1600 (DDR200). The only problem with this is that you'll be constricting the memory bus and hurt performance. High-performance RAM may require a higher voltage to work at it's top speed, but many motherboards allow for some RAM voltage adjustment should this be required. You can get faster RAM, but if you pair it with slower RAM, you'll be limited by the slower stuff.
Are you saying that if you pair two faster DIMMs, say PC6400, they will run at 800mhz? even though zaibutzu's motherboard only supports PC4200 (533mhz)?
Not quite. If they're placed in a situation where the can run at 800MHz, they will. If they're unable to function at 800MHz, they'll run at whatever speed designated without issue. If you're running two speed grades of RAM, the motherboard should automatically set the RAM speed according to the slower memory.
