The speed of a space drive, or any spacecraft, depends on various factors, including the technology used and the specific mission requirements. the fastest spacecraft ever built by humans is the Parker Solar Probe, which was launched in 2018. It is designed to study the Sun and has achieved speeds of up to about 343,000 kilometers per hour (213,000 miles per hour) relative to the Sun.
However, it's worth noting that there are theoretical propulsion concepts and technologies being explored that could potentially achieve much higher speeds in the future. Some of these include ion propulsion systems, nuclear propulsion, and concepts like solar sails or laser propulsion. These technologies are still in development and have not been used in practical missions yet, so their actual speeds and capabilities are uncertain.
It's also important to consider that the speed of a spacecraft is relative to a reference frame. For example, a spacecraft's speed can be measured relative to the Earth, the Sun, or even other celestial bodies. The choice of reference frame can affect the perceived speed of the spacecraft.