The capacity of QSFP (Quad Small Form-Factor Pluggable) modules varies based on the specific variant. QSFP modules come in different types, each supporting different data rates and capacities. As of my last knowledge update in January 2022, here are common QSFP types and their respective capacities: 

1. QSFP:

• Capacity: QSFP modules typically support data rates of up to 40 gigabits per second (Gbps). They are commonly used for 40 Gigabit Ethernet (40GbE) connections.

2. QSFP+:

• Capacity: QSFP+ modules support higher data rates, up to 100 Gbps. They are commonly used for 100 Gigabit Ethernet (100GbE) connections.

3. QSFP28:

• Capacity: QSFP28 modules further increase the data rate to 100 Gbps per lane, providing a total capacity of 100 Gbps (4 lanes). They are commonly used for 100GbE connections and are also part of some higher-speed deployments, like 128G Fibre Channel.

4. QSFP56:

• Capacity: QSFP56 modules support data rates of 200 Gbps per lane, resulting in a total capacity of 200 Gbps (4 lanes). They are used for 200GbE connections and other high-speed applications.

5. QSFP-DD (Double Density):

• Capacity: QSFP-DD modules offer even higher capacity, supporting data rates of up to 400 Gbps per module. QSFP-DD achieves this through an increased number of electrical lanes.

The evolution of QSFP technology reflects the industry's efforts to meet the growing demand for higher bandwidth and faster data rates in data center and high-performance computing environments. The capacity of QSFP modules is directly tied to their supported data rates, and newer variants are designed to accommodate the increasing need for faster and more efficient data transmission. Keep in mind that developments in networking technology may introduce higher-capacity variants in the future.