Performance and fit
Air volume and air speed answer different questions
CFM and MPH are easy to place beside each other on a product page, but they describe separate characteristics. CFM is the published volume of air per minute. MPH is air velocity. A strong, concentrated stream and a broader high-volume stream can feel different in use even when both are sold as “powerful.” Neither number says on its own how long a property takes to clear.
Read the nozzle condition
Manufacturers often list their highest air-speed figure with a tapered nozzle attached. The attachment concentrates the flow and can raise velocity. Some manuals also identify the maximum CFM at the nozzle without associating it with one attachment. Do not assume a speed claim applies unchanged to every nozzle in the box. The tapered, flat and spread nozzles are alternative setups, not parts to attach at once. When an exact manual ties a number to one nozzle, keep that condition with the number.
The EGO manual-listed maximums in this library help illustrate why the measures are not interchangeable. The LB6150-family manual lists 615 CFM and up to 170 MPH with its tapered nozzle; the LB6700-family manual lists 670 CFM and 180 MPH with that nozzle. For the LB7650 body, the current page advertises 200 MPH while the linked manual lists 195 MPH. This review uses the manual's number as a manual specification and calls out the page difference rather than merging the two claims.
Published peaks are not field measurements
CFM and MPH do not incorporate how wet or compact a pile is, how close the tube is, the angle of the air stream, the operator’s technique, or wind. Airflow directed at gravel may move stones, while the same air swept across hard paving can move dry leaves without lifting grit. Wet material may call for a shorter, more concentrated pass and may still resist movement. A single maximum rating cannot represent each surface or debris condition.
Use product specifications to rule in or out a technical floor you truly need, then ask whether the actual nozzle and power configuration support that operation. If you do not have a real minimum CFM or force requirement, leave the optional advanced questions blank and compare the practical package tradeoffs instead. A higher figure can matter, but it is not a universal score or a guarantee of more usable clearing power for every homeowner.
Keep runtime and speed claims separate
Runtime is another specification that depends on conditions. A manufacturer may show a maximum low-speed figure, a high-speed figure, a boost figure or an average mixed-use statement. These are not equivalent. The EGO LB8800 manual gives approximate times with one 4.0 Ah battery, while its current LB8803-2 page describes up to 90 minutes with two included packs. The LB7650 manual and current page also present different runtime figures. Compare the exact operating mode and pack count; do not assume a maximum low-speed estimate applies while holding boost.
Read the LB6151 review, LB6703 review and LB7654 review for the manual-page distinctions, and the finder for optional CFM and force floors. If your purchase depends on a highly specific speed or runtime, confirm the exact current manual for the configuration before relying on a retail summary.