does a 4 GB 1600 MHz RAM affect overall system performance with a 4 GB 1333 MHz ram combined

Solution
You might have to manually tell the system to run the ram at 1333Mhz, but if they do run together it will just give you 8GB of system memory, which can speed things up. Depending on your system you are probably running 4GB @1600Mhz in single channel mode but when you add the 4GB 1333Mhz in many systems it will now be running in dual channel mode so you will actually have a much higher memory bandwidth. Once again this depends on the system as some really low end systems use cpu's that only support single channel memory. Most mainstream systems support dual channel for the past decade.
You might have to manually tell the system to run the ram at 1333Mhz, but if they do run together it will just give you 8GB of system memory, which can speed things up. Depending on your system you are probably running 4GB @1600Mhz in single channel mode but when you add the 4GB 1333Mhz in many systems it will now be running in dual channel mode so you will actually have a much higher memory bandwidth. Once again this depends on the system as some really low end systems use cpu's that only support single channel memory. Most mainstream systems support dual channel for the past decade.
 
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