I currently have two 256 meg chips in my computer. I have two slots empty. I'm looking to put another 512 chip in. The current chips say PC400 on them. I think that means they are DDR 400 megahertz. My motherboard has an 800 mhz system bus so I think the RAM is dual channel to take advantage of that (does that make sense?). This is the motherboard I have... http://www.intel.com/products/motherboard/d865perl/index.htm I'm not sure what kind of memory to buy. It says the motherboard supports DDR 400 (is that dual channel?). I'm also not clear about what the PC3200 means. Do I want PC3200? How do I know. Anyway, I'm Canadian and want to buy from a Canadian source (no duties) like... http://www.tigerdirect.ca/applications/category/category_slc.asp?CatId=147& Any help you guys can give me would be really appreciated.
Dual channel isn't actually related to the clock speed its a motherboard feature that gives roughly a 10% increase in memory performance. You have DDR400 modules. They actually run at 200MHz, but because they are DDR(Double Data Rate) they have an effective speed of 400MHz. PC3200 is a naming convention for RAM speeds. To find the clock speed you can divide the PCxxxx rating by 8. So DDR400 and PC3200 are the same. And to add to the confusion, your 800MHz bus is actually 200MHz quad pumped to an effective 800MHz (although the real life speed is barely half of that). So the RAM and FSB of your system is actually 200MHz (DDR400). If you want detailed information on your RAM, download the small [google]CPU-Z[/google] program which tells you a lot abot your CPU/RAM. Any PC3200 DDR RAM should be fine for you. The expensive modules overclock better but I've never really had a problem with the cheap stuff myself.
Cool. I just bought 1 gig DDR 400 dual channel (2x512). Question: Can I leave in the 512 meg (2x256) or do I have to take it out (something about you can only have intervals X2, ie. 64,128,256,512,1024, etc...)
Not if you want the dual-channel function to work. This would depend on what your doing and the specific program you're using. It may be more beneficial to sacrifice the 512MB for dual-channel 1GB operation. If you're not playing something like FEAR or Battlefield 2 on moderate to high settings, you're looking at diminishing returns past 1GB. However, if you do, or you run a lot of things at once, the extra RAM would be a better benefit.
I want to clarify that the 512 that was in there was dual channel. So all my RAM will be dual channel. Do I still need to leave out the 512 to take advantage of the dual channel? Thanks. BTW: I don't do gaming anymore (no time, I wish) but I do have a bad habit of opening dozens of apps at once.
If I have my info correct, dual channel needs to have the same amount of RAM in each channel to reap the benefits. Now, weather the DC mode can be had with 256+512MB in each channel is going to be determined by the chipset. The most flexible chipset with dual-channel is the SiS 655FX (don't quote me, but it was a DC DDR SiS chipset). Again, given what work you do, the dual-channel function probably isn't nearly as important as the increase in RAM.
