Which is not a part of Dell's desktop portfolio?

The Gaming Razer brand does not belong to Dell's desktop portfolio, as it is associated with Razer Inc., a company known for its gaming hardware and peripherals. Dell's desktop offerings include specific brands that cater to various market segments, including corporate, consumer, and gaming.

OptiPlex, XPS, and Inspiron are all established lines within Dell's desktop family. OptiPlex is designed primarily for business environments, focusing on reliability and manageability. XPS caters to high-performance and premium users, whereas Inspiron targets mainstream consumers looking for a balance of performance and value. Each of these lines reflects Dell's strategy to address the needs of different customer segments, thus reinforcing their position in the desktop market.