dual channel memory question

[acejj26]

last week, i jumped on the core 2 duo bandwagon. bought a C2D 6400, Gigabyte 965p-s3 motherboard and 1 GB of DDR2-800 RAM (2 x 512). if i were to buy a 2 GB kit, could i populate the four memory slots so that I'm still running the memory in a dual-channel configuration?

also, is it possible to lower the memory ratio under 1:1 so i can keep increasing the FSB but keep my memory frequency low? i'm currently at 400 MHz (so the cpu is running at 3200 mhz) but so is my memory and i don't really know where the memory will top out. i want to try to find the ceiling of the processor/mainboard. is this possible?

 

[acegazda]

Usually when running 4 sticks of RAM, mobos will default to single channel. IDK if you can set it to dual channel.
Why would you want to keep your memory frequency low? Just oc your RAM to 400mhz... unless you have value RAM, in which case you'll have to set up that 3:4 or w/e.

 

[Paperdoc]

I don't know about "default to single channel" operation. But I have read that many motherboards will slow down the memory access substantially when the 4 slots are populated. Some, however, can then be set back manually to full speed in the BIOS. Don't know the specifics of your board.

One thing you're gonna get right, though, is the max RAM you can use. Most versions of Windows cannot address more than 4GB of memory, and up to 1 GB of that address space is used by system functions. So even if you have 4 GB or RAM, the system can only use 3. (The exception is if you install the 64-bit versions of Windows that can handle larger memory address spaces.) So your proposal, to put in 1 GB plus 2 GB of dual-channel RAM would work well. Just make sure the 2 x 512 MB sticks are in one pair of dual-channel slots, and the 2 x 1GB in the other pair.

 

[acejj26]

let's say i think the FSB can top out at 500 MHz but my memory is good to only 400. so i'd like a memory multiplier that is 4:5 instead of 1:1 so that i can run a faster bus and faster processor speed.

in regards to the memory, wouldn't it be the 512 sticks run in alternating channels and the 1 gb sticks run in alternating channels?

 

[Bobthelost]

Yes you can. I don't think 775 boards take much if any hit by going to 4 sticks, less than A64/AM2 does at the worst (and that's pretty negligable).

However you're going to get better overclocks from 2 sticks than 4 in all likelyhood. Odds are that when you can afford the 2GB kit you still won't need more than 2GB so selling it on would make sense.

 

[myocardia]

Originally posted by: acejj26
let's say i think the FSB can top out at 500 MHz but my memory is good to only 400. so i'd like a memory multiplier that is 4:5 instead of 1:1 so that i can run a faster bus and faster processor speed.

in regards to the memory, wouldn't it be the 512 sticks run in alternating channels and the 1 gb sticks run in alternating channels?

First, if you run 4:5, your memory will be faster than your fsb. So, you're wanting to run 5:4, which you won't be able to do. The 965 chipset can't run the RAM any slower than 1:1.

You're also right about where the new 1GB sticks would go. You would keep the 2x512MB sticks where they are now, and put the 2x1GB sticks in the other two slots. You will need to use identical sticks (same IC chips, with the same timings, at the same speeds), since you're overclocking. And bobthelost is right-- having four sticks of RAM can cause you to end up with a lower overclock.

 

[acejj26]

stupid 965 chipset....hopefully my memory won't hold me back. i think 3500 would be an awesome overclock (would require a 875 MHz FSB, about 10% faster than what my RAM is rated)

thanks for the replies, guys....i appreciate it