Dual Channel with 3 sticks of RAM?

[muzikfreakah]

---

the two mems will work in dual, the other in single. BUT, you have to make sure your mems are compatible with the same timings. Trial and error gyud ni. We just made one work. All corsair mems to iya. 2x256 and 1x512.

Make sure you insert the two in the dual channel slots.

[[DSX]]

additional info on nforce2 boards which support dual channel and has 3 mem slots:
======= <-- DIMM 1 channel 0

======= <-- DIMM 3 channel 1
======= <-- DIMM 2 channel 1

dual chan config assuming identical chips:
1x256MB/DDR400@slot1 + 1x256MB/DDR400 on either slot 2 or slot 3= dual chan 512MB@400Mhz
1x512MB/DDR400@slot1 + 2x256MB/DDR400 on chan 1= dual 1GB@400Mhz
1x512MB/DDR333@slot1 + 2x256MB/DDR400 on chan 1= dual 1GB@333Mhz

in short... channel 0 must be equal to channel 1 in terms of size else they will run in single channel mode. the whole system will run at the speed of the slowest chip on either modes.

RDRAM's -- it's another story, they must come in pairs and all the slots must be filled else use CRIMM's

[EarlZ]

as long as naay solod ang DIMM Slot 1 , and another sa DIMMSlot 2 and or 3

im using 1GB on DIMM Slot 1 and 512MB 2X on slots 2 and 3, dual channel man =)

[[DSX]]

as long as naay solod ang DIMM Slot 1 , and another sa DIMMSlot 2 and or 3

not entirely accurate
channel 0 in this case is dimm1 and channel 1 is composed of dimm2 and dimm3. channels 0 and 1 must be equal in size to operate in dual channel mode. if you put your 1Gig in either dimm2 or dimm3-- it will operate in single channel mode only try it hehe

[muzikfreakah]

I agree DSX, good info man!

[EarlZ]

in other words just read the damned manual..

dia ra diay akogn arrangement sa mem


5 5 1
1 1 G
2 2 B
M M
B B

not boot detected as dual channel ^_^

didnt notice any perforamce drops if sa igon ana nga set-up dili mo allow ug dual channel. 3dmark scores are still d same. but windos is uber fast. labi na mag duwa kag game from 1600x1200 then mo quiit ka.. reposnive ang windows dayun ^_^ this 1GB wont be here to stay for long ^_^

[jiro]

@jiro: you seem to know a lot about dual channel coz you got long posts.... i dont know where you learned those but dual channel does not mean doubling mem freq. thus:
2xDDR400!=800Mhz in dual mode but still in 400Mhz --this time running in 128-bit rather than only 64bit in normal mode. and yes 3 rams at dual channel mode works! (not all boards support this.. if you have 4 mem slots.. most probably it wont work in dual channel)

opo

it is still in 400mhz only this time running at 128bit.

I have a question that still bothers me...
CPU FSB: 400MHz X 8 bytes = 3.2Gb/s peak Memory Bandwidth
Single-channel memory DDR 400= 400MHz X 8 bytes = 3.2Gb/s peak bandwidth
Dual-channel memory DDR400=400 MHz X8 bytes X 2 channels = 6.4Gb/s

Correct me if im wrong...
theory 1 - You computer will use dual Channel. BUT only peaks at 3.2GB/s
,
your 3rd Memory sLot also uses at 3.2GB/s, so i guess, its ok to use the Third Slot.
this led me to conclusion that the first memory will run at dual channel and the other at single channel only.

This will not work if you have 800fsb... (will peak at 6.4Gb/s)
CPU FSB: 800MHz X 8 bytes = 6.4Gb/s peak Memory Bandwidth
Dual-channel memory DDR400=400 MHz X8 bytes X 2 channels = 6.4Gb/s

im trying to look at manuals and sites at reference about the 2slot dual and 1 single.

As for my p4. 3slot will defenitely not work. it will only run at single channel if you use 3 slots.

[EarlZ]

dba ang dual channel ana mana,


instead of the system can access 1 ram module @ a time, kung dual channel ka pwede mag dungan access 2 or more memory modules thus a result of twice the theoretical bandwidth

[jiro]

im looking for (see page 8. ) sa amd...
http://www.kingston.com/newtech/MKF_...whitepaper.pdf

in P4 manuals, it clearly says single mode for 3 rams.

im trying to look for AMD version of this. basig naa sa inyung manual?

[grss1982]

wow, posted this topic a few months back and its still going strong.

thanks for all your input regarding the topic guys!!!!