Some RAM Slots do not detect the sticks either in BIOS or WINDOWS

First of all, there is nothing to "change" as far as channel operation is concerned. If memory is installed and is compatible, with each other and with the board and chipset, they will automatically assign the operating method, single, dual, flex, etc. There is nothing you need to do in regard to this aside from making sure you install pairs into the proper A and B channels for each pair. Some boards will need each "Pair" installed in slots 1 and 2, others will want them in 1 and 3 and still others may call for single pairs to be in slots 2 and 4.

You need to refer to the motherboard manual for population rules.

Secondly, if you populate the pairs in the correct slots, and they don't work together, they may simply be incompatible. The only way to guarantee compatibility for certain when using multiple modules is to purchase the full number of modules to be used in a matched set. If you plan to use two sticks of RAM, buy a set of two. If you plan to use four, buy a set of four. They need to be tested at the factory for compatibility with each other to guarantee compatibility.

That does not mean however that pairs of unmatched sets CAN'T work together, but there are no guarantees. Even two pairs that each came together, two and two respectively, that are the exact same part numbers for all four modules, but did not come together all in one set, may not work together. The more differences there are, brand, speed, latency, voltage, in each set of modules specifications, the more likely they are to not work together.

I'd begin by checking to see that you are populating the correct pairs in the correct slots, and go from there. Aftermarket motherboards are a lot more likely to have broad support for different brands and speeds, as well as compatibility among disparate sets of memory, than OEM motherboards that come in prebuilt systems are going to have.

Your board supports:

•Two independent memory channels with interleaved mode support
•Support for non-ECC, unbuffered, single-sided or double-sided DIMMs with x8 organization and single-sided DIMMs with x16 organization
•32 GB maximum total system memory (with 4 Gb memory technology)
•Minimum total system memory: 512 MB
•Serial Presence Detect
•DDR3 1333 MHz and DDR3 1066 MHz SDRAM DIMMs


And the slot closest to the CPU plus the third slot over are one used for one set. The second and fourth are used for the second set.

look at all 4 dimms. make sure there all the same voltage. older memory used to be 1.65 and newer ram is 1.5v. some of the newer ddr3 ram is 1.35v. look at the ram itself make sure all ram is single sidded or dd sided ram dont mix them. also count the number of chips on the ram. make sure there all the same. you can have issues if one set uses 4 chips and one set uses 8 chips.

You're correct, there shouldn't be any variance in the specifications if you bought all four modules of the exact same part number within a relatively short period of time. If there have been a significant amount of time passed, it's possible to have a discontinued part number recycled for use with a newer module that has different specifications, but that generally only happens years after the original part first released and then was discontinued.

Using the same part number does not however guarantee they will play nice together. If they are not all purchased together in a matched and tested set, they may not work. Further, when using all four memory slots it may be necessary to slightly increase the DRAM voltage in order to make them stable or to have them recognized.

Further, if you have some modules that are blue and some that are black, then they are not the same model numbers. What are the part numbers of every module you have?

Ok, I see what you mean now. The slots themselves are blue and black. No worries, on the same page now.

So, those are very low end modules. I think it's highly probable that you either have a bad stick or you have modules that are slightly different enough, even though they are the same model, that they don't want to work together. Try using one one single module, each module one at a time, in the slot designated for use when only one module is to be used. See if any of them doesn't want to work. Next, try combinations of three modules, swapping out for another module each time all three are recognized, using slots 1, 2 and 4. If you find the module that's causing you issues, return it for replacement. If you can't pin it down to one particular module, then it's likely they will simply not play nice together and you may have to purchase a matched set of four modules of the proper specifications in order to use all four slots.

Have you updated the BIOS/ Tried the voltage adjustments, etc

Using an older BIOS can result in a slew of different problems. They provide updates for a reason. Incompatibilities with specific memory types or speeds, or profiles, or voltage settings, is often one of those reasons. If you don't have the latest BIOS, get it and install it.

As to the memory voltage, absolutely it can affect recognition and performance. I've seen many cases where a simple bump up in memory voltage resolved memory problems, modules that weren't recognized or lack of proper operation modes.

Tradesman1 is probably about the most experienced person you're ever likely to find on any forum, or at least within the top five, so if he suggests you should try something, I would not take it lightly.