Originally Posted by
LastBronx
Not bad but definitively : a double clocked SH2 (57.2 mhz) was not possible in 1993/94; 28.6 mhz was the fastest speed available at this time for the SH2.
At first, I also thought the dual SH2 setup was shitty but it was not so. Getting the max out of it was difficult but not impossible and was nearly achived very early in Saturn life cycle (see Sega Rally or Virtua Fighter 2. Even Virtua Fighter Remix and Panzer Dragoon made good use of both the SH2). Sega should have provided their tools (even scaled back) to third parties to help them to program the 2 SH2.
The SH2 was a very good cpu for its time and is almost the only good piece in the Saturn. In 1993, there were not numerous options for Sega for cpu to choose. A MIPS R4000 based cpu would have been more expensive than 2 SH2 (even 3 of them I think) and not more powerful. A MIPS R3000 based one would have been too weak (remember than the Playstation R3000A has on-die embedded coprocessos like the 66 mips gpe that give it its polygonal capabilities).
What Saturn needed is a faster dsp. At 57.2 mhz instead of 14.3 mghz, the Saturn SCU one would have been very powerful. And Sega could have kept both the SH2. With such a dsp, developpers wouldn't have had to rely such on the second SH2 so that it could have been used for sound controlling and processing (along with a simple 16 bit DAC) by lazy programmers and for further 3d effects by good devs...
There were also too many buses in the Saturn and too many memory pools of memory of different types. That's why Saturn was so expensive to produce ans was to remain so during all its life cycle because it was almost impossible to consolidate. One unique pool of 2 to 4 MB of sdram on a 64 bit bus (with why not a 2x speed latch mechanism) would have been very good. It wouldn't have been a problem for the 2 SH2 thanks to their 4 KB cache (as it wasn't a problem for the R4300i in the N64). The VDP1 had to be tweaked to create a framebuffer in this pool. It would have been more flexible as you could choose the framebuffer size or it to be double buffered or not on demand. The VDP1 also desperately needed to be able to render triangles. Allowing quads (mainly for 2D) and triangles (for 3D) would have been a dream. As they were working on the Model 2 board with Lockeed Martin by this time, they could have tried to include functionalities that even the Playstation lacked : perspective correction (even partial) texture mapping and bilinear filtering of textures. To summerize, my dream saturn would be
- Sega CD based CD controller and dram (Motorola 68000 and 128 KB of cheap dram).
- Dual SH2 setup (same as actual Saturn).
- Single VDP : VDP1 on a 64 bit bus (128 bit 2x latch?). banwidth : 228.8 (457.6 with 2x latch) MB/s against 135.2 MB/s for the Playstation (and more than 550 MB/s for the N64).
2 KB cache ram for texture lookup tables.
2 to 4 KB cache ram for texture buffers.
2 to 4 KB cache rom of generic textures.
Partial perspective correct texture mapping (subdivided texture mapping).
Bilinear filtering.
RGB and YCbCr (for Gouraud shading) colors.
- Simpler SCU : one main bus
Really fast dsp (57.2 mhz).
Embedded 16 bit stereo DAC in the SCU.
All of this would have been nothing without good dev tools, clever marketing and solid managing. Sega should have launched the Saturn on september 1995 in USA like originally planned. I don't think they needed to sell it at a 299 dollars price point. IMHO, early adopters don't really care about price but they do really care about value for the price. A399 dollars Saturn with 2 package games (let's say Bug and Virtua Fighter Remix) would have offset the Playstation 299 dollars price point for one year until N64 launch and prevent Sega to lose too much money on each sold console).