>    The major problem is not the speed, but the amount, as I mentioned.
> The architecture would be fine, the problem is that the amount of RAM
> is puny compared to modern game requirements. If the Xbox360 had, for
> example, 2GB of RAM (or more), then it would really be a killer gaming
> platform.

Don't forget games for the PC that quote 1GB or 2GB RAM requirements 
need to accomodate the Windows OS and all other running services and 
apps as well as the game itself.  I would be quite surprised if any game 
for Windows actually used 1 or 2GB of RAM just for itself - apart from 
caching files from disc on the way to the GPU, what else would a game 
need that much CPU RAM for?

Post a reply to this message

> I just noticed that things on the PS3 seem less ... shiney. :-) Like,
> there's much more detail in batman's cape on the xbox than the ps3, from
> what I can notice without having them physically side-by-side. Maybe the
> dev tools for that sort of thing are easier on the xbox, so more work
> goes into making it prettier. Or it might just be my imagination. :-)

I haven't played on the xbox360 very often (I don't own one) but my 
impression is games on the PS3 use motion-blur and depth-of-field 
approximation effects more.  Maybe the devs are just trying to find ways 
to use up the spare CPU cores, but often it makes the game look quite 
bad in still shots, when you can see that they are just faking the effects.

Mind you, apart from the shadows (why use low resolution shadow map 
textures in such a polished game??), Gran Turismo 5 is beautiful.

Post a reply to this message

On 01/04/2011 08:49 AM, scott wrote:

> Don't forget games for the PC that quote 1GB or 2GB RAM requirements
> need to accomodate the Windows OS and all other running services and
> apps as well as the game itself. I would be quite surprised if any game
> for Windows actually used 1 or 2GB of RAM just for itself - apart from
> caching files from disc on the way to the GPU, what else would a game
> need that much CPU RAM for?

While I would imagine that most of that is texture data, and possibly 
models, a chunk of it is probably sound data too. Depending on the game, 
it might also need to store non-trivial amounts of gameplay data.

Post a reply to this message

> While I would imagine that most of that is texture data, and possibly
> models,

I imagine a good written game-engine (like a good written OS) will use 
up whatever unused resources it has available to the benefit of the user 
- in this case filling up the CPU RAM with a cache of GPU data that 
might be needed soon.  But it's not a minimum requirement for such RAM 
to be available, it's just loaded directly from disc a few frames 
earlier (big CPU<>GPU transfers are spread out over many frames anyway) 
if the files aren't in the cache.

> a chunk of it is probably sound data too.

Didn't think of that, I guess uncompressed CD-quality sound takes up 10 
MB or so per minute, maybe this is used a lot by PC games, IDK.  At 
least when using XNA with the xbox, the sounds/music are stored in some 
compressed format, it wouldn't surprise me if they are decompressed 
on-the-fly to avoid using up too much RAM.

> Depending on the game,
> it might also need to store non-trivial amounts of gameplay data.

Yeh, this is the main point I was wondering about, apart from graphics, 
what sort of data might a game need to store that runs in to several 
hundred MBs?  I couldn't think of anything straight away.

Post a reply to this message

>> a chunk of it is probably sound data too.
>
> Didn't think of that, I guess uncompressed CD-quality sound takes up 10
> MB or so per minute, maybe this is used a lot by PC games, IDK. At least
> when using XNA with the xbox, the sounds/music are stored in some
> compressed format, it wouldn't surprise me if they are decompressed
> on-the-fly to avoid using up too much RAM.

Yeah, MP3 or similar seems to be the norm here. (And these days, 
decoding MP3 takes so little CPU power...)

>> Depending on the game,
>> it might also need to store non-trivial amounts of gameplay data.
>
> Yeh, this is the main point I was wondering about, apart from graphics,
> what sort of data might a game need to store that runs in to several
> hundred MBs? I couldn't think of anything straight away.

I know when I looked at the HalfLife 2 engine, you needed to build 
navigation maps to allow the NPC AI to navigate around the map. That's 
not model data as such (it never goes near the GPU), but it's data that 
you do need to run the game. On the other hand, for a typical HL2:DM or 
CS:S map, it's only a dozen MB or so...

Post a reply to this message

scott <sco### [at] scottcom> wrote:
> I haven't played on the xbox360 very often (I don't own one) but my 
> impression is games on the PS3 use motion-blur and depth-of-field 
> approximation effects more.  Maybe the devs are just trying to find ways 
> to use up the spare CPU cores

  Those effects are not dependent on the CPU.

-- 
                                                          - Warp

Post a reply to this message

scott <sco### [at] scottcom> wrote:
> Don't forget games for the PC that quote 1GB or 2GB RAM requirements 
> need to accomodate the Windows OS and all other running services and 
> apps as well as the game itself.

  The OS doesn't take half a gigabyte of RAM. That would be ridiculous
(even for Windows). You can actually see the amount of free RAM from the
task manager, and there's usually just some tens of megabytes less than
your total amount of physical RAM in the worst cases.

  And you shouldn't be running RAM-heavy apps at the same time you are
playing.

-- 
                                                          - Warp

Post a reply to this message

scott <sco### [at] scottcom> wrote:
> Yeh, this is the main point I was wondering about, apart from graphics, 
> what sort of data might a game need to store that runs in to several 
> hundred MBs?  I couldn't think of anything straight away.

  The scene geometry cannot be loaded all at once onto the GPU RAM if the
scenery is huge (which is the case at least with open sandbox games and even
non-sandbox ones if the scenery is very detailed). The scenery has to be
loaded dynamically as the player moves. The more RAM you have, the less
loading needed and the faster the game.

-- 
                                                          - Warp

Post a reply to this message

>> I haven't played on the xbox360 very often (I don't own one) but my
>> impression is games on the PS3 use motion-blur and depth-of-field
>> approximation effects more.  Maybe the devs are just trying to find ways
>> to use up the spare CPU cores
>
>    Those effects are not dependent on the CPU.

The CPU is routinely used for graphics effects in the PS3, here's the 
first reference I could find via google:

"We're doing all the post-processing effects on the Synergistic 
Processing Units." Screen Space Ambient Occlusion for example, was done 
completely on the SPUs"

http://en.wikipedia.org/wiki/Uncharted_2:_Among_Thieves#Graphics_and_technology

Post a reply to this message

>    The scene geometry cannot be loaded all at once onto the GPU RAM if the
> scenery is huge (which is the case at least with open sandbox games and even
> non-sandbox ones if the scenery is very detailed). The scenery has to be
> loaded dynamically as the player moves. The more RAM you have, the less
> loading needed and the faster the game.

Why should loading the scenery from disc slow down the game?  It's done 
in the background before you get to the part of the level where the 
scenery is needed (the same way stuff is transferred from the CPU RAM to 
the GPU RAM on PCs).  Otherwise it would be impossible to race around a 
huge areas like the Nurburgring (or cities on GTA) on the PS3 without 
"Loading..." screens half way around (which would be a little stupid for 
a car driving game) :-)

Post a reply to this message