Dual channel RAM

What exactly are the requirements for running dual channel RAM? I assume that both DIMMs need to be the same size. Do they both need to be the same speed? (PC 3200 vs PC4200)

What are the advantages of dual channel? Speed, I suppose, but how much? I have heard that it may be of particular advantage with integrated video.

I have 512 mb PC3200. I am thinking of upgrading with either another 512 or 256. Honestly 768 will be plenty for me. On average I am using 250-300 out of 512. I believe that includes the amount allocated to integrated video. (It is a total-free calculation.)

If I can get a speed boost, it might be worth the extra money to get 512 even though I don't really need it for the memory.

If I understand things correctly, another stick of PC3200 will also utilize my 533 fsb capability that is not currently being used with the 400 msb PC3200. Is that correct?

 

biggest requirement for dual channel is that your motherboard supports it or not. After that both sticks of RAM should be identical for the best performance. Though I believe all that is actually necessary is both sticks need the same density. However if one stick is faster than the other, you get the speed of the slower stick.
I'm not getting what you mean with the PC 3200 using 533 MHz Bus, but PC 3200 RAM is going to run at 400 Mhz. Getting another stick of isn't going to make it so they use 533 Mhz, just 400 x 2 theoretically.
As for the extra money you should probably just get anothe 512 MB stick since it's only about 50 dollars vs 25 dollars. RAM seems to be pretty consistent in its pricing so 1 gig of RAM is about 100 dollars twice the size and the price of 512 MB which is twice the size and price of 256 MB.

 

i highly agree with dblank. You need to check what your motherboard supports for your speed of ram, and you really should get teh same size. You wont be "speeding up" the ram but you will increase the bandwidth of the usable ram thus giving a bit of a performance enhancement. I believe if im not mistaken both channels act in a sort of RAID configuration, esentially boosting speed but not technically

 

My question is slightly off topic but I don't want to devote a separate thread to it.


I have 2x512MB of RAM. I noticed that I rarely go beyond using 400MB.

Does the extra 512MB just heat my laptop, so that I better remove unless
I do a RAM consuming application (really rarely, and only when I am stationary). Will I notice a diference in terms of the battery live and/or fan activity. If someone can estimate how many Watts extra 512 RAM takes,
I can estimate the rest. I have PC3200.

 

ivar, there you go http://www.valueram.com/datasheets/KVR400X64SC3A_512.pdf (that's kindstons datasheet, but I think all are pretty much the same!)

I don't think it will matter much in terms of battery consumption. As for heat, the sensor is on the CPU, so the heat from the RAMs wont force the fans on/off.

 

Thanks for the answer!

So, the number I found in the spec is 3.6W. Does it mean that my extra 512MB RAM takes around 3 Watts of power even when I don't need this memory for my applications? It's a lot!
In my notebook the RAM is packed pretty close to the processor, so it may heat up the processor.

 

might as well leave it in there though. The ram itself wont heat up enough when idle to make the processor heat up, or even set off the fans. Even in low amounts of shared ram processing, it wont do much at all. Also that 3w you see wont change but minutes on your battery life. And if you're so concerned with a couple minutes on your battey, then you need to be looking for a new battery

 

I am rather concerned with the annoying fan going on rather often. If the period would change from 12 minutes to 15, it would make me happier. Are you saying that RAM takes much less than 3 Watts when idle? If so, I would leave it like it is, indeed.