Sega Model 2

From Sega Retro

Model2 cpu.jpg

Fast Facts on the Sega Model 2

Made by: Sega

Release Date RRP Code
Arcade JP 1993 ¥?  ?
Arcade World 1994  ?

The Sega Model 2 is an arcade system board originally debuted by Sega in 1993 as a successor to the Sega Model 1 board. It is an extension of the Model 1 hardware, most notably introducing the concept of texture-mapped polygons, allowing for more realistic 3D graphics (for its time). The Model 2 board was an important milestone for the arcade industry, and helped launch several key arcade franchises of the 90s, including Daytona USA, Virtua Cop, Sega Rally Championship, Dead or Alive, Virtua Striker, Cyber Troopers Virtual-On and The House of the Dead.

The Model 2 was engineered with help from GE Aerospace (acquired by Martin Marietta in 1993, now part of Lockheed Martin), who designed the texture-mapping technology incorporated by the Model 2. The Model 2's development was led by famed game designer Yu Suzuki. The Model 2 arcade board debuted along with Daytona USA, a game which was finished, copyrighted and debuted at the JAMMA arcade show in 1993.[1]

There four versions of the system: the original Model 2 and the Model 2A-CRX, Model 2B-CRX and Model 2C-CRX variants. Model 2 and 2A-CRX used a custom DSP with internal code for the geometrizer while 2B-CRX and 2C-CRX used well documented DSPs and uploaded the geometrizer code at startup to the DSP. The Model 2 was succeeded by the Sega Model 3 in 1996.


It was a further advancement of the earlier Model 1 system. The most noticeable improvement was texture mapping, which enabled polygons to be painted with bitmap images, as opposed to the limited monotone flat shading that Model 1 supported. The Model 2 also introduced the use of texture filtering and texture anti-aliasing, [2] as well as trilinear filtering.[3] It was the most powerful game system in its time, equivalent to the power of a PC graphics card in 1998, five years after the Model 2's release.[4]

Designed by Sega AM2's Yu Suzuki, he stated that the Model 2's texture mapping chip originated "from military equipment from Lockheed Martin, which was formerly General Electric Aerial & Space's textural mapping technology. It cost $2 million dollars to use the chip. It was part of flight-simulation equipment that cost $32 million. I asked how much it would cost to buy just the chip and they came back with $2 million. And I had to take that chip and convert it for video game use, and make the technology available for the consumer at 5,000 yen ($50)" ($84 in 2014) per machine. He said "it was tough but we were able to make it for 5,000 yen. Nobody at Sega believed me when I said I wanted to purchase this technology for our games."[5] Suzuki stated that, in "the end," it "was a hit and the industry gained mass-produced texture-mapping as a result." For Virtua Fighter 2, he also utilized motion capture technology, introducing it to the game industry.[6]

There were also issues working on the new CPU,[7] the Intel i960-KB, which had just released in 1993.[8] Suzuki stated that when working "on a brand new CPU, the debugger doesn't exist yet. The latest hardware doesn't work because it's full of bugs. And even if a debugger exists, the debugger itself is full of bugs. So, I had to debug the debugger. And of course with new hardware there's no library or system, so I had to create all of that, as well. It was a brutal cycle."[9]

In a late 1998 interview, Read3D's Jon Lenyo, a former employee of GE Aerospace (later Lockheed Martin), stated that Sega's development for the Model 2 can be traced back as early as November 1990, when he and other GE Aerospace employees visited Sega and demonstrated the trilinear texture filtering and shading capabilities of their technology. As Sega was already working on the Sega Model 1 internally, they eventually incorporated GE Aerospace's technology into the Model 2.[10]

Despite its high price tag of around $15,000[11] (equivalent to $24489 in 2014), the Model 2 platform was very successful. It featured some of the highest grossing arcade games of all time: Daytona USA, [12] Virtua Fighter 2, Cyber Troopers Virtual-On, The House of the Dead, and Dead or Alive, to name a few. Sega sold 65,000 units of the Model 2 annually,[13] and eventually sold over 130,000 units by 1996, amounting to over $1.95 billion revenue from hardware cabinet sales (130,000 units[14][15] at $15,000 each[16][17]), equivalent to over $3.18 billion in 2014, making it one of the best-selling arcade systems of all time.

Technical Specifications

Main CPU (central processing unit)
GPU (graphics processing unit) video hardware
Audio hardware
RAM (random access memory)

Total RAM: 9776 KB (Model 2/2A-CRX), or 18,388 KB (Model 2B/2C-CRX)

  • Main RAM: 1152 KB (9 Mbits) (1024 KB work, 64 KB network, 64 KB serial)
  • Video memory: 5984 KB (Model 2/2A-CRX), or 14,596 KB (Model 2B/2C-CRX)
    • Framebuffer VRAM: 1024 KB (Model 2/2A-CRX), or 1536 KB (Model 2B/2C-CRX)
    • Coprocessor buffer SRAM/SDRAM: 64 KB (Model 2/2A-CRX), or 8228 KB (Model 2B/2C-CRX)
    • Texture memory: 4096 KB SRAM/SDRAM
    • Luma: 128 KB (Model 2/2A-CRX), or 64 KB (Model 2B/2C-CRX)
    • Other: 672 KB (32 KB geometry, 576 KB tiles, 64 KB colors)
  • Audio memory: 576 KB
  • Backup SRAM/NVRAM: 16 KB
  • Extra RAM: 2048 KB
Graphical capabilities

List of Games

Model 2

Model 2A-CRX

Model 2B-CRX

Model 2C-CRX



Sega Arcade Boards
Originating in Arcades
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