The Nitro 640 LX 2005 vs Nitro NX 750 SC 2006 comparison sits squarely in the category of decisions where specs alone won't tell the whole story — intended use, storage, and long-term ownership costs all factor in.

On paper these two are close siblings in the size department — Nitro 640 LX 2005 at 16,0 ft versus Nitro NX 750 SC 2006 at 17,0 ft. Weight tells a clearer story for trailering families: the Nitro 640 LX 2005 tips the scales at 1 092 lbs — 957 lbs more than the Nitro NX 750 SC 2006 at 135 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.

The power gap is worth calling out. Rated to 135 hp, the Nitro NX 750 SC 2006 has a 45-hp advantage over the Nitro 640 LX 2005's 90-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Nitro 640 LX 2005 carries 24 gallons versus 3 gallons in the Nitro NX 750 SC 2006. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.

For family outings this is probably the sharpest distinction between the two. The Nitro NX 750 SC 2006 is rated for 5 passengers, while the Nitro 640 LX 2005 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Nitro NX 750 SC 2006 could be the deciding factor.

At this size, power-to-weight ratio matters more than outright horsepower. The Nitro NX 750 SC 2006 comes in at 1 lbs per hp versus 12 lbs per hp for the Nitro 640 LX 2005. The lower the ratio the more explosive the acceleration — meaningful on a short RIB where bursts of speed, quick planing, and agility in surf or tight waterways define the experience.