General off-road speeds for all vehicles are very fast, but with tanks it is especially noticeable. Fast tanks like the T-100 move at crazy velocities, speeds at which the crews would be bumped around inside hard enough to be completely unable to observe and fire.
Further, the high speeds make even the AI outrun its situational awareness, causing them to get destroyed because they barreled right into an enemy team of AT riflemen without spotting them, after speeding into them from three kilometers away at a breakneck pace.
Combat AI also always moves at the highest possible speed. This is okay, the top speed just needs to be lower.
For reference, typical combat speeds for tracked vehicles are between 5 and 15 mph (reference the US tank gunnery manual FM 17-12 "Tank Gunnery" Chapter 6 Section V, Page 130). T-100s sometimes reach nearly 70 kph off-road, along with extremely rapid and go-kart like movements that make them less than believable.