Impmon said:
7800 has a completely different CPU (backward compatible with 6507
used by 2600), addition of extra RAM, and a separate video chip. 2600
mode used the Stella chip while 7800 mode used the Maria chip.
Probably the least radical of all bacward compatible console and on
par with Gameboy Color (different CPU but worked with older games)
The difference was very substantial. The Atari 400/800 computers and
Atari 5200 (same chipset in console and computers) were a major jump in
power over the 2600 but the 7800 had distinct advantages over those. It had
the same 256 color palette as the GTIA (one of the co-processor pair in the
Atari 800) but supported modes allowing more colors onscreen before
resorting to special programming tricks (like changing the color registers
as the screen was drawing so that different horizontal bands could have
different groups of four colors), supported larger and much more numerous
sprites. Oddly the sound in the 7800 relied on the same chip from the 2600.
Some 7800 games had better audio by including a POKEY chip from the 400/800
in the cartridge.
It was a bit of a mystery why Atari didn't instead produce a more
powerful version of the ANTIC, GTIA, and POKEY chips so they could made a
major upgrade to their computers as well as a new console platform. further
down the road they could have done as Apple did with the ][GS, creating a
16-bit backward compatible system using the 65816. (Also used in SNES.) Part
of the reason may have been that Atari had made a substantial cash
investment in Amiga before they were acquired by Commodore and were
expecting the new system to be sold under an Atari label and eliminate most
interest in a improved 800 series system.
Not long after the 7800 was announced Atari was sold to the Tramiel
family that had founded Commodore and were ousted from that company. The
Tramiels weren't interested in putting up the capital for marketing a game
system, so the 7800, games and everything else that had already been
manufactured just sat in a warehouse for years. They eventually dumped it
all on the retail market for a small fraction of what it had cost Time
Warner to make. There were a few third party titles but only a small number
of the available games ever made good use of the system.
The 7800 was doomed for reasons other than technical abilities. Even if
it had been released as scheduled and beat the NES to market it would have
lacked Nintendo's most important contribution to the console business: the
business model that made third party publishers a source of revenue rather
than competitors. Interestingly both game systems would have several of the
same titles since Atari had licenses for several of Nintendo's hits like
Donkey Kong, Donkey Kong Jr., and the original Mario Bros. game. All of
these had very poor version on the 7800 though, which was surprising
considering the very good version on the Atari computers and other computers
through the Atarisoft brand.
I'd say the 7800 is somewhat less of a leap than that from GBC to GBA.
The GBA is a completely different ISA while all of the Atari 8-bit products
used some form of 6502 or derivative.
