If you want to add memory, you must check the memory frequency and the generation of DDR.

How can I check the DDR memory speed?

The CPU-Z software is very good. Although it detects the CPU, it can also detect the motherboard and memory, and its functions are unambiguous! It can detect whether the CPU is too frequently, whether it is 32-bit, the model of the motherboard, the number of memory slots of the motherboard, the model and speed of the memory, etc.

Run CPU-Z and click the "Memory" tab to clearly display the memory frequency.
The 133mhz is ddr266.
The value of 166mhz is ddr333.
MHz is ddr400

CPU-Z v1.33 in Chinese
Http://www.onlinedown.net/soft/2775.htm

DDR 266 333 400 belongs to a generation of memory
DDR2 533 667 800 1066 all belong to 2 generations of memory