Dual-processor systems
* 2.4GHz system: 1066MHz DDR3 ECC SDRAM
* 2.66GHz and 2.93GHz systems: 1333MHz DDR3 ECC SDRAM
Single-processor systems
* 2.8GHz and 3.2GHz systems: 1066MHz DDR3 ECC SDRAM
* 3.33GHz system: 1333MHz DDR3 ECC SDRAM
There are no 8GB 1333 MHz chips so the limit is 32 GB with such modules.