Apple computer users who upgrade to the Snow Leopard operating system can expect to save about 10 percent in electricity a year.

Considering Apple’s annual sales of about 10 million computers, the savings will translate to more than 80 million kWh a year, or nearly $10 million in electricity, calculated against a power systems review of the new operating system from CNET.

On an individual basis, the improvement is a drop in the bucket, however.

An Apple Macbook Pro 17-inch using the OS X Leopard 10.5.6 system will consume about 85.09 kWh annually, costing about $9.66. By comparison, using the OS X Snow Leopard 10.6 will consume 76.74 kWh annually, costing about $8.71, reports CNET.

Total savings? About 95 cent per computer.

The cost to upgrade existing machines to the new OS is $29.