sega's use of the SH-4

[PowerPC300]

when sega was developing the dreamcast, they had a choice, use a PPC 603e, or use an untested chip, the HITACHI SH4. sega chose the latter, because hitachi was a japanese company, and had close ties already by providing the SH2 for the saturn. the first use of the SH4 was the sega naomi arcade hardware, paired with a powervr2 GPU. 1999 would see the release of the dreamcast and hikaru (my 2nd favorite arcade board ) dreamcast is just a naomi with less ram, hikaru on the other hand is special, for the only time, the hikaru had 2 CPU's instead of one, and a custom GPU replaced the powervr GPU found on the naomi. however, the hikaru was too expensive to produce with all of it's custom parts, so the naomi 2 was developed, it was a downgrade, with just one CPU but had 2 powervr2's to make up for it. it also had the elan T&L chip, making it more powerful than the playstation 2. (sometimes i wonder why sega should have used the naomi 2's specs for the dreamcast instead of the naomi's) when the dreamcast was discontinued, sega had to get rid of their surplus of SH4's. sega then created the system SP or spider. it runs a custom version of linux and is paired with a powervr MBX+VGP, the same GPU as the iphone's GPU.

[MetalliC]

I can't say Sega really was developing Dreamcast/NAOMI platform, they was more like customer in restaurant, where actual chief/cooks was 3DFX who developed 'Dural' PPC603e+Voodoo3 hardware, and Hitachi+ImgTec+NEC who developed 'Katana' SH4+PVR2 hardware.

in the same time Sega (as far as I know) itself was developing Hikaru (codename 'Samurai'), custom and expensive arcade platform, spiritual successor of Sega Model 3.

in about 2nd half of 1998, right after NAOMI and Japanese Dreamcast release, ImgTec started work on next generation of Dreamcast/NAOMI hardware, with ELAN T&L chip and 2x PowerVR2 GPUs, which was released 2001 in arcades as Naomi 2.
however, I'm personally sure it was initially planned for home market, as Dreamcast 2.
its also not correct to say "Naomi2 was downgrade of Hikaru", as it have nothing with it, and I think N2 is more powerful than Hikaru in GPU part, but less powerful than Playstation2 GPU.

SystemSP was nothing new, but cost reduced NAOMI 1, where on single mobo was embedded: Flash ROM board, Network board (AMD AU1500 based), IO and CF interfaces. JVS MCU and interface was removed.

in about mid-2000x, SI Electronics Ltd (Sammy subsidiary at the time, who also developed Atomiswave, and in late 2000x System Board Y2) developed 'Aurora' hardware, which was based on single chip, which included SH4 and PowerVR MBX+VGP, and used Linux as core OS.
but it seems was never released, at least we haven't seen any released games which uses such hardware.

as for SH4 CPUs - Sega used them in all kinds of IO boards: NAOMI/Triforce/Chihiro DIMM board, hopper controllers, camera image recognition boards, JVS IO board for some Lindbergh games, etc.

[PowerPC300]

the hikaru can do phong shading, the PS2 and naomi 2 could not, it could do more than the dreamcast, how could it not be more powerful than the PS2?

[MetalliC]

you are talking about features, not power (performance).
for example: Dreamcast/NAOMI can do trilinear texture filtering and super-sampling, but they are soo slow, so was never used at practice for whole rendered scene. only small number of games uses these features, for very small number of objects onscreen, while the rest of scene rendered as usual.

yes, probably Hikaru had per-pixel lighting (i.e. phong), and presumable had 'cheap' or even 'free' trilinear filtering, but what was system performance at practice (fill rate, polygon rate, etc) ? we still don't know.

on other hand, PS2 has HUGE fill rate, which was used in many games for all kinds of impressive effects.
Dreamcast and Naomi 1/2 had ^^this not even near comparable to PS2, and I'm sure Hikaru too, and has significant less power in term of performance.

[PowerPC300]

Oh, sorry.

[PowerPC300]

I think the hikaru was just a prototype naomi 2, the hikaru has powervr gpu's but had a custom T&L copro, while naomi 2 had a videologic designed one. Naomi 2 also got rid of the 2nd SH4.

[MetalliC]

I'm afraid you are wrong, in every sentence.

also it goes off topic in this forum.

[doteater]

yea , off topic festival

metallic , i'm about to test demul on my "new" setup
fingers crossed because i can't stand nulldc's limitations anymore

[VirtuaHunter]

Always interesting to read detailed specs of the Sega hardware, thanks

Speaking of Hikaru and Naomi 2, MetalliC any news of improvements of Demul emulation? I'm really looking forward for improvements especially to Virtua Fighter 4 and Planet Harriers

[ferrarifan]

This Topic should be on the Demul fourm. Your subject isn't related to Supermodel,Model 3,and it's games.