The PC Duo is a 2-in-1 desktop computer combo released in 1996 until 2004. It is houses two computers inside one casing, one is the main board (for running Windows 95 and other known operating systems) and one is the DOS-compatible single-board computer. Only the 1999-2003 models features the single-board DOS-compatible computer attached to it, the 1996-1998 models didn't it. It also houses a turbo button on all of the models. However, on 1999-2003 models, it is separated to the DOS-compatible single-board computer instead.
The first model of PC Duo features a Pentium Pro/Pentium II processor, without the single-board computer mounted on it. The first model allows to run DOS-compatible software via a software version of the Turbo button, which features 3 CPU modes:
- 386 mode (used for games that are released in the late-1980s until the early 1990s)
- 286 mode (used for games that are released in the early to mid-1980s)
- 4.77Mhz mode (used for early IBM PC games)
The latter models utilizes a single-board iDX4 computer mounted onto the main computer board, which includes a turbo button rather than a software implementation of the Turbo button.
The 1996-1998 models features a Pentium Pro/Pentium II processor, 32-64MB of internal memory, 500MB-2GB hard drive, and an ATi Mach64GX video card with a 3Dfx Voodoo video card on it.
The 1999-2003 models features a Pentium III processor with a single-board iDX4 computer mounted onto the main computer board, a wide range of memory from 64-256MB, 4-8GB hard drive for Windows and other x86-compatible OSes and 2GB for MS-DOS. Plus, it includes 2 x USB ports and it includes a more advanced ATi graphic card, plus a VESA-compatible video card (known as DuoVGA) is also included, which runs a wide-array of DOS programs that uses CGA/EGA/MCGA/VGA/VESA video modes.
The PC Duo uses a BIOS that is similar to most IBM-compatible computers in the 1990s, however, it uses a BIOS that also allows to boot to the single-board iDX4-based computer, which this BIOS is only present on the 1999-2004 models.
DuoVGA is a video chip used in 1999-2004 models of PC Duo, it allows to run DOS-compatible programs without any issues or glitches, it supports the following video modes:
An enhanced version, known as DuoVGA+ was released.