04-10-2012, 06:33 PM
As snow suggested, since you are running 3x memory modules I would assume that you are running a first gen core i7 configuration with triple channel memory (x58 LGA1366 I believe). If this is true then, depending on your MB, there's a couple possibilities that I would see, which might occur.
Your system may not even be able to boot up. There are a few reasons that would cause this.
1. Some of the early model, lower end MBs were limited to 12 GB (6x2GB) or may have a max module size of 2GB. Most boards support 24GB in either 4 or 8 GB modules so this is unlikely.
2. The MB may not allow you to run a triple channel configuration in 1 memory bank and a dual channel configuration in the other. Also not very likely.
3. As snow said--don't mix different modules sizes in the same memory bank. Chances are the system will not boot if you do this.
4. I assume by "I bought the same exact RAM..." you mean the same speed and voltage. If either set of these modules are not compatible with the frequency and voltage of the other then your system will not boot.
If you have a decent MB and didn't do any of the things listed above, it is likely that everything will boot up just fine. One thing is for certain, however. The bank that is running with only 2 memory modules will be limited to dual channel access, which will impose a small performance penalty whenever your CPU has to access large amounts of data from that memory bank.
If you do add another chip so that you're running 3x2GB and 3x4GB modules you will see a maximum capacity of 16GB in your OS. Remember that the 16 GB is an artificial limit of the OS software (must be 64-bit, obviously) and not necessarily of the hardware, itself.
Your system may not even be able to boot up. There are a few reasons that would cause this.
1. Some of the early model, lower end MBs were limited to 12 GB (6x2GB) or may have a max module size of 2GB. Most boards support 24GB in either 4 or 8 GB modules so this is unlikely.
2. The MB may not allow you to run a triple channel configuration in 1 memory bank and a dual channel configuration in the other. Also not very likely.
3. As snow said--don't mix different modules sizes in the same memory bank. Chances are the system will not boot if you do this.
4. I assume by "I bought the same exact RAM..." you mean the same speed and voltage. If either set of these modules are not compatible with the frequency and voltage of the other then your system will not boot.
If you have a decent MB and didn't do any of the things listed above, it is likely that everything will boot up just fine. One thing is for certain, however. The bank that is running with only 2 memory modules will be limited to dual channel access, which will impose a small performance penalty whenever your CPU has to access large amounts of data from that memory bank.
If you do add another chip so that you're running 3x2GB and 3x4GB modules you will see a maximum capacity of 16GB in your OS. Remember that the 16 GB is an artificial limit of the OS software (must be 64-bit, obviously) and not necessarily of the hardware, itself.