DCTP - SEGA's Naomi 2 Technical Overview

SEGA's Naomi 2 Technical Overview
SEGA Naomi 2 Technical Specifications

SEGA's incredible Naomi 2, that allows full backwards compatibility with Naomi 1 games, and has the amazing new feature of a very powerful transformation and lighting engine. This will insure that SEGA continues to dominate the arcades with cost effective, and powerful hardware.

Introduction

SEGA first showed Naomi 2 at the Japan Amusement Machinery Manufacturers Association (JAMMA) Fall 2000 arcade show in Tokyo, Japan which took place from September 21st to the 23rd.

It's been two years now since SEGA debuted the original Naomi arcade board at JAMMA Fall 1998, and in that time Naomi has come to dominate the arcade scene with both SEGA and Capcom releasing quite a few games on that hardware.

Naomi 2 Specifications

CPU
CPU: 200 MHz Hitachi SH-4 (SH7091)
CPU Memory: 32 MBytes (100 MHz SDRAM)
CPU Memory Data Path: 64-bits
Memory Bandwidth: (800 MBytes/sec)

Geometry Co-processor
Geometry Co-processor: VideoLogic custom transformation & lighting (T&L) chip (Code named: ELAN)
Clock Rate: 100 MHz
Sustained Polygonal and Lighting Rate: 10 million polygons/sec with 6 light sources!
Supported Lights: Ambient, parallel, point and spot
Vertex Support: Combined dynamic and static model processing
Geometry Memory: 32 MBytes
External Memory Data Path: unknown
Memory Bandwidth: unknown

Graphics Processing Unit (x2)
GPU: Two PowerVR2 (CLX2)
Pixel Fill-Rate: 200 MPixels/sec (400 MPixels/sec to 600 MPixels/sec due to infinite plane architecture assuming depth overdraw complexity of 2 to 3 layers)
Graphics Memory: 2 x 32 MB (100 MHz SDRAM)
External Data Path: 64-bits per GPU (128-bits total)
Memory Bandwidth: 800 MB/sec per GPU (1.6 GB/sec total)
Graphic Effects: Polygons/strips/fans engine, 16-bit and 24-bit color, multiple fog modes, super sampling for full scene anti-aliasing, specular highlighting, texture filtering: bilinear, trilinear, anistropic, MIP mapping, bump mapping, perspective correction, 8-bit alpha blending (256 levels of transparency), ARGB gouraud shading, general modifier volumes (GMV) for such effects as shadows, light, transpararency, etc.

Note: SEGA listed 2,000 MPixels/sec for the fill rate, and there is no point in listing that here, as that is not realistic. That assumes an overdraw of 10x and no game has that kind of overdraw.

Other
Sound Engine: 45 MHz Yamaha ASIC with ARM7 CPU core supporting 64 channels of 48 KHz, 16-bit sound (64 channel ADPCM)
Sound Memory: 8 MB DRAM

Media: ROM board, optional GD-ROM drive
Display: Dual monitor support
Communications: RS232C serial port
Game Port: JAMMA video system (JVS)

Geometry Coprocessor

Naomi 2 has a dedicated geometry coprocessor to handle transformations and lighting which is rated at 10 million polygons per second with 6 light sources. Note that the T&L processor is not limited to 6 lights, as a maximum of 16 lights per polygon can be achieved, but with a reduction in the polygon rate. The geometry chip will offload all T&L calculations previously performed by the 128-bit matrix math unit on the SH-4. The SH-4 will now be free to devote more of its resources for physics, artificial intelligence, collision detection and overall game code. The hardware T&L unit features combined dynamic and static model processing, and multiple light type support (ambient, parallel, point and spot).

Almost all T&L processors on the market never state what their polygon rate is with the number of light sources present per polygon, and the reason why, is because the polygon rate goes way down with more light sources, with the current T&L processors on the market. T&L should always be rated with number of polygons with number of light sources present. Note: the lighting information for a polygon does not have to be related to a light source, as light information can also be used to make an object look more realistic. Like trying to make plastic look like plastic in a game.

Dual Graphics Chips

Two PowerVR2 (CLX2) GPU's with 32 MB of memory each, which is twice the amount that the PVR2 GPU had on the Naomi 1 board. Each chip renders half the screen (rectangular, stripes, and checker board options), so game textures have to be repeated in both local memory pools, but the display list (infinite plane) data covers only the area of the screen that each GPU has to render.

Overall Bandwidth

Hard to determine the exact overall bandwidth, as SEGA has not released the data path size for the geometry coprocessor. It most likely would be 32-bits or 64-bits in size, and we will assume 64-bits to help give us a rough ideal on the overall bandwidth. If it is only 32-bits, then the final total below would be 400 MB/sec less.

Data Path	Bandwidth
CPU SH-4 <-> 32 MB Main Memory	64-bits x 100 MHz = 800 MB/sec
"ELAN" Coprocessor <-> 32 MB Memory	64-bits x 100 MHz = 800 MB/sec
1) PVR2DC <-> 32 MB Graphics Memory	64-bits x 100 MHz = 800 MB/sec
2) PVR2DC <-> 32 MB Graphics Memory	64-bits x 100 MHz = 800 MB/sec
Total:	~3.2 GigaBytes/sec

Total overall bandwidth is roughly twice the bandwidth of Naomi 1. Note that the PowerVR GPU's can push the equivalent of 2 to 3 times their bandwidth as compared to a traditional renderer, so that would give the comparative overall bandwidth to be roughly 5 to 6 GigaBytes/sec. Note: I did not include the sound sytem which also has it's own local memory pool.

Motherboard

Click to Enlarge Click to Enlarge Naomi 2 motherboard showing the geometry processor (under heatsink), the SH-4 CPU (upper middle part of the board), and the two PowerVR2 (CLX2) chips (under the fans).

Click to Enlarge Naomi 2 daughterboard showing two DIMM slots and can contain 256 MB of memory in these configurations: 128 MB x 2 or 256 MB x 1. This DIMM daughterbord is needed for the games that will be distributed on GD-ROM's. Sports Jam (WOW Entertainment) for the Naomi 1 is the first game to be distributed on a GD-ROM disk.

Naomi 2 & Naomi 1 cases Back of Naomi 2 case Naomi 2 case Motherboard and daughter board

All pictures courtesy of Gary Evans (DCTP Japanese correspondent) and also IGN's Naomi 2 article and were taken at the JAMMA Fall 2000 arcade show.

Load Balancing

Naomi 2 shows excellent load balancing between processors and local memory pools. The three most computational tasks for a 3D game is:

Game AI & Code
Transformation and Lighting
Rendering

The Naomi 2 board has a dedicated processor and local memory pool for each of the three major tasks in a 3D game. This will help minimize processor contention for the three tasks, and allow for more efficient memory accesses. This efficient segmented memory design allows for the use of cheaper single data rate SDRAM's instead of DDR SDRAMs. At the time of this writing SDR SDRAM is much cheaper than DDR SDRAM, but soon DDR SDRAM will achieve similar pricing as volume production is ramped up. Note: The sound system also has it's own processor and memory pool, so it's tasks and resources will not interfere with the other processors.

GD-ROM Distribution

It was at the JAMMA Fall 2000 arcade show that SEGA showed off a new distribution method for arcade games, as both the Naomi 1 and Naomi 2 boards allow a daughter board for RAM, and both allow GD-ROM drives to be hooked up. The RAM daughter board holds the game to be played that is spooled off of the GD-ROM. This will help eliminate any load times.

The Games

The first games announced for Naomi 2 at the JAMMA Fall 2000 arcade show were:

Virtua Striker 3 (Amusement Vision)
Wild Riders (Wow Entertainment)
Club Kart Racing
Virtua Fighter 4 (AM2)

Virtua Striker 3, Wild Riders, and Club Kart Racing were shown in video form only at the show. Virtua Fighter 4 will make it's first appearance on February 23rd/24th, 2001. The first games will be released in early 2001.

So far only SEGA has announced Naomi 2 games, and hopefully Capcom will also support this new board, as strongly as they have supported the Naomi 1 board.

Links

Naomi 2 Press Release
JAMMA 2000: IGN's article on NAOMI 2 Game Footage
JAMMA 2000: IGN's article Naomi 2 Revealed with movies of the Technical Demos
Virtua Fighter 4 website