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First of all, I have the Asus M4A87D-M PRO motherboard. enter image description here

And I have now two identical Apacer 2GB PC-6400 CL5 800Mhz sticks installed. I am going to buy a Transcend JetRAM 2GB PC2-6400 CL6 800Mhz stick.

How do I put all the 3 ddr2 dimms in the slots shown above so they will be stable and there won't be memory channel conflicts?

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Did you go to the Asus site and download the user manual? Did you do any research prior to posting this question? – Moab Dec 16 '11 at 16:10
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What he said. Twice! – OG Chuck Low Dec 16 '11 at 16:11
    
Also... Am I reading you correctly in that you are going to have 6GB total on a dual channel Motherboard??? If I AM reading that correctly, can I ask WHY you would do such a thing? Splurge, get one more stick and that will also answer your question won't it? – OG Chuck Low Dec 16 '11 at 16:14
    
Yeah but can I get 2 more 1GB sticks? or they all have to be 2GB sticks? – develroot Dec 16 '11 at 16:22
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Your card clearly support at least 8GB, if you want to do this, then order two identical Apacer 2GB PC-6400 CL5 800Mhz and it should work just fine. If you cannot find that brand, then order four Transcend JetRAM 2GB PC2-6400 CL6 800Mhz. – Ramhound Dec 16 '11 at 17:30
up vote 2 down vote accepted

The answer is YES

BUT

Do not install non even number of ram.

This will cause ALL your ram to run at half speed.

Insert them in pairs..

If you really want to do then you can put it in any available slot. Does not matter, and you can mix and match makes- because it is fairly generic ram, with generic timing and speeds.

Using 3 stick might cause your boot screen to beep, or moan that the ram is running half duplex, is uneven or might even show 400mhz instead 800mhz. That is normal. When you get another stick, it will get back to normal, but make sure they are all 800mhz

If you are putting in specific ram with boosted performance. then all 4 need to be the same so you can get the best performance.

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can I have my 2x2GB apacer and add 2X1GB other ram? – develroot Dec 16 '11 at 16:26
    
To be more clear. Yes. But it will run half speed – ppumkin Dec 16 '11 at 16:27
    
so it doesn't matter i have an even number of ram, if they are not all the same, they will run at half speed, right? I think adding this: memoryc.com/computermemory/ddr2ram/… to my current 2x2GB apacer slots, will it work normal? – develroot Dec 16 '11 at 16:32
    
To clarify this... if you fill each color bank with a 2gb stick and 1gb stick they will ALL run at normal full speed (unless you have literally mixed speeds and then they will all max out at the highest speed the SLOWEST chip can hit). The Half speed I think Pump is referring to is that you is from the UNEVEN number of sticks. – OG Chuck Low Dec 16 '11 at 16:57

Quick Answer:

For the Asus M4A87D-M PRO motherboard put the Apacer 2GB PC-6400 CL5 800Mhz sticks in DIMM-A1 and DIMM-B1 and put the Transcend JetRAM 2GB PC2-6400 CL6 800Mhz in DIMM-A2


Detailed Answer:

Typically your motherboard manual will indicate some order in which to populate the DIMM slots. Motherboards which support Dual-channel architecture can run two or more DDR type memory modules in dual-channel configuration. Theoretically, dual-channel configurations double the memory bandwidth when compared to single-channel configurations though it would seem that this may result in little to no real world performance increases (see this article)

DIMM Socket Color Codes:

Motherboards supporting dual-channel memory layouts typically have color-coded DIMM sockets. Coloring schemes are not standardized and have opposing meanings, depending on the motherboard manufacturer's intentions and actual motherboard design.

Matching colored DIMM sockets may indicate one of two possibilities depending on the motherboard:

  • Matching colored sockets belong to the same channel and indicate that DIMM pairs should be installed to differently colored sockets

  • Matching colored sockets belong to different channels and indicate that DIMM pairs should be installed to the same color.

Guidelines for dissimilar memory modules:

  1. Modules rated at different speeds can be run in dual-channel mode, although the motherboard will then run all memory modules at the speed of the slowest module.

  2. Some motherboards, may have compatibility issues with certain brands or models of memory when attempting to use them in dual-channel mode. For this reason, it is generally advised to use identical pairs of memory modules (matching capacity (eg: 1024MB), Speed (eg: PC5300), CAS Latency, Number of chips and sides, etc.)

  3. For maximum performance, populate the sockets so that the memory capacity is spread as equally as possible between two Channels. A matched pair of memory modules may usually be placed in the first bank of each channel, and a different-capacity pair of modules in the second bank. eg: 2x 2GB DIMMS in Channel A and 2x 1GB DIMMS in Channel B.

  4. For systems with only 1 DIMM socket you have no option (runs in Single Channel mode)

  5. For systems with 2 DIMM sockets place the largest memory capacity DIMM into the first DIMM socket i.e. Channel A, Bank 1 and the second in Channel B, Bank 1.

  6. For systems with 3 DIMM sockets place the largest memory capacity DIMM into Channel A, Bank 1, place the second largest memory capacity DIMM in Channel B, Bank 1 and the third DIMM in Channel A, Bank 2

  7. For systems with 4 DIMM sockets place the largest memory capacity DIMM into Channel A, Bank 1, place the second largest memory capacity DIMM in Channel B, Bank 1, the third largest memory capacity DIMM in Channel A, Bank 2 and the fourth in Channel B, Bank 2.

References:

  1. Asus M4A87D-M PRO motherboard manual page

  2. Tom's Hardware - "Parallel Processing, Part 2: RAM and HDD"

  3. Multi-channel memory architecture

  4. HP Support

  5. Lenovo Support

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