The Group Alliance@IBM said layoffs have included more than 220 in marketing and 165 in semiconductor research and development.
At least 100 workers have been laid off from four other divisions: STG Storage Systems Development, GBS AMS IBM Global Account, the Software Information Management and Industry Solutions, Fox Business reported.
Workers have also posted notices of smaller numbers of layoffs across the organization.
Individuals who have been laid off have also posted notices online.
"I work in STG in 3D Edram Development and was informed of permanent layoff today," one employee wrote.
"Atlanta POS Group hit hard. Storage and other groups hit too. Typical package," wrote another.
Alliance@IBM, which is aligned with the Communications Workers of America union said there had been a total of 1,634 job cuts.
The company had said more layoffs would take place in the third quarter, but had not said how many would be let go.
The company expects to pay $1 billion in charges related to the layoffs, Chief Financial Officer Mark Loughridge has said.