Multi-channel memory *should* work in theory even if the RAM stick PCBs and chips are different manufacturers. A RAM manufacturer like GSkill or Corsair will build/buy their PCBs and populate it with RAM chips from another manufacturer like Samsung, Hynix, or Elpida. AFAIK only Crucial (Micron) makes their own PCBs and RAM chips in house. Multi-channeling will still work as long as the PCB + chips are rated to run at the same voltage, speed, and memory timings. But obviously matching everything up is a lot harder the more contributing factors are different... and keep in mind that manufacturers might be using different PCBs or RAM chips even in the same series of RAM sticks, but never would use different components in the same SKU. So as long as your SKU/part number and revision is the same you should be OK. Otherwise if the right DIMMs are populated your mobo will still attempt to run in multi-channel by use the highest denominator voltages, timings, and speed (basically it'll default to the slowest stick). If that can't be done then it drops down to single-channel
