Possibly. It depends on the motherboard, CPU, and memory specifications.
To maximize memory bandwidth, it is usually preferred to install memory of same capacity in dual channel configuration.
Installing a 2 GB module and an 8 GB module will provide less bandwidth and performance than using two modules of same capacity. 2 x 4 GB ( = 8 GB total memory) modules from a dual channel kit might be a better option.
What is the make and model of motherboard and CPU?