From: tclark@hptc.mentorg.com (T Clark)
Subject: Re: SG vs. Snes
Date: Thu, 28 Jan 1993 21:29:23 GMT
Organization: Watsamatta U
Keywords: 
Followup-To: 

I hate it when a good argument is ruined by misquoting the facts...


In article <1993Jan27.184107.10594@mprgate.mpr.ca>, vanderby@mprgate.mpr.ca (David Vanderbyl) writes:
|> davem@uvmark.uucp (Dave Meeks) writes:
|> 
|> >The SNES "generally" has better sound and more colors, but 
|> >the Genesis "generally" has faster games with more on-screen sprites.  
|> >Also, the SNES "sometimes" suffers from slowdown, occasionally severe, and has
|> >shown that it has an inferior, underpowered processor.
|> 
|> Why do people keep repeating this garbage over and over?
|> The SNES is just simply technically superior.  Here are the facts:
|> 
|>                   Sega    SNES
|> Max # sprites:      80     128
|> Max sprite size: 32x32   64x64
|> Max # colors:       64     256
|> Palette:           512   32768
|> Max resolution 320x280 640x480  (These are approx. from memory)

First, you specs here do not match what is in the FAQ. According to the FAQ
the highest resolution for SNES is 512 x 448 and in that mode you can only
get 16 colors on screen. Also the FAQ indicates that the sprite sizes are
equal, ie 32x32. 

|> 
|> The reason the SNES is more technically advanced is that Nintendo spent
|> an extra year (or two?) developing it.  This is the same reason that
|> there are more different games for the Sega Genesis.

There is simply no correlation of data that indicates that the longer you
develop a product the more technically advanced it will be.

|> 
|> As for game slowdown, this is a factor of the PPU (picture processing unit).
|> The Nintendo's "processor" (I guess you meant the CPU) is in fact superior,
|> since it requires less code to do the same thing as the Sega's.  It is true
|> that the Nintendo runs at half the speed of the Sega, but this does not
|> affect performance, it's the PPU that causes slowdown.
|> 

I am not so sure that you can prove that the 65816 requires less code than
a 68000 to complete the same function. It may be possible in some cases, but
I am sure that the 68000 can do some functions more efficiently than the 65816.
Also, I would be interested to see what the specs are on the PPU. The PPU has
to get data from the processor, unless it has some sort of DMA (direct memory
access) transfer capability. 

|> Incidentally, much is made of the Nintendo's 8 bit data bus to the CPU.
|> Let me explain why this is not an additional speed factor.
|> When the Sega Genesis wants a word of memory it says "OK memory, give me
|> a 16 bit word".  When the Nintendo wants a word of memory is says
|> "OK memory, give me the first half of the word, then give me the second
|> half of the word".  BUT, this is why the Nintendo's clock it half as fast
|> in the first place, because it needs to make two memory accesses.  Thus the
|> processor is exactly half as fast (3.56 Mhz vs 7.12 Mhz) not one quarter
|> as fast as some people try to say.
|> 

This argument is so bogus, I just don't know what to say. First, when the 68000
asks for a word (16 bits) of memory it has the capability to get that in one
memory cycle, but only if the memory is fast enough to allow the processor
to run with out any wait states (waits states are basically wasted CPU cycles).
The 65816 must take 2 memory cycles to fetch the same 16 bits and if it has to
do this at half the speed (ie 3.56 Mhz vs 7.12 Mhz) then the total time to 
fetch a full 16 bits of memory will take 4 times as long (simple math - 
2x cycles taking 2x the amount of time = 4x cycles per amount of time)

So to summarize, the processor may in fact have slower memory accesses but
there is not enough information to determine that it is inferior to the 68000.
For example, the 65816 has built-in I/O ports that most likely can be accessed
directly by the CPU and depending on what Sega is using for I/O in the
Genesis the 65816 might be superior in this way. Graphics processing is most
likely the key component in any home video game. Having the ability to 
scale and rotate on-screen objects with graphics hardware is by far
superior to doing it with a CPU and software. Furthermore, slowdown
may be cuased by a number of factors including, CPU speed, Graphics capability,
poor programming and so forth. Which is the better machine? Well, if you
want to play SFII then SNES is the winner. If you want to play SONIC II then
Genesis wins hands down! So you see, you can't really judge a video game
by its hardware.

Cheers
T Clark
-- 
T C

e-mail: tony_clark@mentorg.com