One model, the 840GM, is powered by Intel's 3GHz Pentium D 830 dual-core processor. The 835GM, meanwhile, is based on the 2.8GHz Pentium D 820 dual-core processor.
The computer maker also released the 831GM, which runs on a 3GHz Pentium 4 processor 630.
All three computers will be available through retail outlets.
Each of the three systems has a DVD-ROM, a 250GB hard drive, and a 16x double-layer, a multiformat DVD+/-RW optical drive.
All the new desktops come with a media manager for reading different digital devices, software for burning CDs and DVDs, a multimedia keyboard, and a USB optical mouse. The 840GM also features a BTX chassis, the company said.
Gateway said the machines were designed with students in mind.
"We created this new line specifically for the needs of students by incorporating all the hardware and software features needed to maximize PC productivity and entertainment," Marc Demars, Gateway's senior director of desktop product marketing, said in a statement.
The 840GM and 835GM will retail for $1,049.99 and $849.99, respectively, starting July 10.
The 831GM will be available for $699.99 starting Sunday, Gateway said.