ASUS P5W DH Dual Channel DDR2 800

rvltion909

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OK So Im pretty new to PC building but just built one off an ASUS P5W DH and Conroe 2.13.

My situation is that Im running about 2.5G Corsair XMS DDR2 800 in what I THINK is dual channel. I just ran CPU Z and am a little confused. I read the RAM FAQ here and from what I gather DDR2 800 "standard" runs at 400MHz...? So I dont get why Corsair says it's supposed to run at 800MHz and why CPU Z says its running at 270MHz and 400MHz in slot and #1 and #2? My mobo says dual channel has to have A-1 + A-2 must equal B-1 + B2 for dual channel and to install in B-1 & A-1 + B-2 & A-2. Does this mean I MUST have 4 stick installed for dual channel?

I've got 2 1G sticks in two slots and 1 512MB in an other for a total of about 2.5G.

When CPU Z refers to "slot 1, 2, 3" does mean A-1, A-2, B-1?

Again, Im not sure Im running in dual channel since all the sticks seem to be running at 270 and 400 when they all should be 800? They are all the same model and speed-one is just 512 and the other 2 are 1G.

Im going to try to take the 512 out tomorrow to see if this makes a difference in the way the freq. is posting and hopefully this will reflect 800. The system runs fine and has been since I set it up like this and performs just fine...however not up to the standards I'd expect for this much RAM.

Since I am new to this Im probably making allot of stupid mistakes and funny assumptions here so any help would be great.

I use this PC strictly for audio use-that's it. I use allot of VST programs that suck up lots of CPU so I want this thing to be a beast and will overclock the CPU soon when I get the right cooling.

Thanks!
 

nobly

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I read the RAM FAQ here and from what I gather DDR2 800 "standard" runs at 400MHz...?
Ok, DDR2-800Mhz really runs at 400Mhz on the motherboard. Its labelled at 800Mhz cuz some marketing folks figured, hey, we can multiply by 2 because it moves 2 pieces of data on 1 clock.

So I dont get why Corsair says it's supposed to run at 800MHz and why CPU Z says its running at 270MHz and 400MHz in slot and #1 and #2? My mobo says dual channel has to have A-1 + A-2 must equal B-1 + B2 for dual channel and to install in B-1 & A-1 + B-2 & A-2. Does this mean I MUST have 4 stick installed for dual channel?
No, it just means that the amount of RAM in the A channel must equal the amount of RAM in the B channel. So you don't have dual channel right now because you're running 3 sticks of RAM. Put 1GB in A1 and 1GB in B1 and it sounds like that'll give you dual channel. The 270Mhz you mentioned might be because one of your chips is rated at DDR-533Mhz?
Or maybe that's the rate your RAM is running at right now?
Screenshot might be worthwhile.

When CPU Z refers to "slot 1, 2, 3" does mean A-1, A-2, B-1?
Not sure.
 

rvltion909

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Yea I figured a screen shot would do nicely but I've got nowhere to post it as the forum doesn't allow html or atch.

Im going to see what taking the 512 out is going to to for me and post back.
 

Mondoman

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You can also try another program, such as PC Wizard 2006. For actual memory speed info (not the SPD data), look under the "Chipset" section in the upper right window, not the "Physical Memory" section.
 

rvltion909

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thanks for the info guys

so yea I took 512 stick out and.....everything is the friggn' same...?

Im running at 333.9 MHz when it should be 400MHz I have no idea why.


And an other thing-is it better to be running 2G dual channel or 2.5G not in dual channel (as far as significant performance gain)?
 

rvltion909

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sweet info Mon! I made the changes in BIOS and PC WIZ says Im now running 400.7MHz 5-5-5-12 in dual mode just like the specs say. My boot up sats PC-6400. DRAM/FSB ratio is 3/2. I set them to 1.9 like Corsair says...but PC WIZ says it at 1.8...? Odd...

It seems stable but I'll run mem test later to confirm.

Couple other questions: ( I see you have a similar setup to me)

I'd like to utilize my extra stick of 512MB (same specs just 512 version) would I be able to sitck it in one of the free slots in channel B (free channel)?

My mobo sheet just says for dual channel both channels need to equal each other but is it possible to run dual channel on one channel and regular on the other (just so that my other stick doesnt go to waste)? Since its the same make and specs. the settings I manually entered whould work for this stick too. Is it worth it?

Im not not sure about your mobo but it looks like you dont have to have both channels equal each other since you've got 3G (2G in one channel and 1G in an other) and both running dual channel-am I understanding right?
 

nobly

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Couple other questions: ( I see you have a similar setup to me)

I'd like to utilize my extra stick of 512MB (same specs just 512 version) would I be able to sitck it in one of the free slots in channel B (free channel)?

My mobo sheet just says for dual channel both channels need to equal each other but is it possible to run dual channel on one channel and regular on the other (just so that my other stick doesnt go to waste)? Since its the same make and specs. the settings I manually entered whould work for this stick too. Is it worth it?

Im not not sure about your mobo but it looks like you dont have to have both channels equal each other since you've got 3G (2G in one channel and 1G in an other) and both running dual channel-am I understanding right?
Dual channel means you have only 2 channels on your motherboard. It does NOT mean that each RAM slot you have it a channel. Note that the slots have A1, A2, B1, B2, as you described earlier. So one channel is the "A" slots and the other channel is the "B" slots. In order to have dual channel, the memory sizes need to be the same in the "A" and "B" channels. So in the case of mondoman, he has 2x1GB and 2x512MB. One 1GB goes to A1, one 512MB goes to A2. The others go to B1 and B2. This meets the requirements for dual channel, each channel now has 1.5GB, for a total of 3GB of total system memory.

So no, you cannot run dual channel on one channel (by definition doesn't make sense).