The speed of a QSFP (Quad Small Form-factor Pluggable) transceiver depends on the specific standard or generation of QSFP module being used. Different QSFP modules support various data rates to accommodate the increasing demand for higher-speed networking. Here are some common QSFP data rates: 

1. QSFP:

• The original QSFP modules supported data rates up to 40 Gbps. These modules are commonly referred to as "40G QSFP" or "QSFP-40G."

2. QSFP+:

• QSFP+ (Quad Small Form-factor Pluggable Plus) modules support data rates up to 100 Gbps. They are used for 100 Gigabit Ethernet applications. These modules are often referred to as "100G QSFP+" or "QSFP+-100G."

3. QSFP28:

• QSFP28 modules support data rates up to 100 Gbps as well, but they are an enhanced version of QSFP+, allowing for higher-density installations and improved performance. QSFP28 modules are commonly used for 100 Gigabit Ethernet applications and are often referred to as "100G QSFP28" or "QSFP28-100G."

4. QSFP56:

• QSFP56 modules support data rates up to 200 Gbps. These modules are designed to meet the increasing bandwidth demands in data centers and high-performance computing environments. QSFP56 modules are often referred to as "200G QSFP56" or "QSFP56-200G."

5. QSFP-DD:

• QSFP-DD (Quad Small Form-factor Pluggable Double Density) modules support data rates of 200 Gbps and 400 Gbps. They are designed to provide higher-density connectivity and accommodate the growing need for faster networking speeds. QSFP-DD modules are often referred to as "200G QSFP-DD" or "400G QSFP-DD."

It's important to note that each generation of QSFP introduces improvements in terms of data rates and capabilities. When selecting QSFP modules for networking equipment, ensure compatibility with the desired data rate and the specific requirements of your network. Additionally, consider the type of fiber (single-mode or multimode) and the reach requirements for your application.