PS3 Has “Tight memory, Poor IO Performance” – John Carmack

[mjk45]

zarx said:

mjk45 said:
The last comment from Carmack I saw had him saying the PS3's CPU was the more more powerful of the two but offset by having a weaker GPU , now this one says equal CPU weaker GPU, looks like he was down playing things either unconsciously or deliberately , What I got from playing Rage isit has a nice 60fps framerate but was a very linear game that gave the illusion of freedom with open vistas let down by hidden barriers , flat lo-res textures and lacking gun play, as a showcase for their mega texture tech it is poor and seeing it will never be used as a first party engine we we will never know for sure how much blame to lay at who's ever door.

The blame lays between the nature of megatextures and the limitations of the hardware. Virtual texturing does one thing well and that is allowing every inch of the game world to be uniquely textured so no 2 areas look the same. Unfortunatly that come with several dissadvantages vs traditional methods the first is that as every inch of the world has it's own texture you have to load in the texture data for every inch of the world and also store unique texture data for the entire world which leads to very large texture data which is why the game is 22GB now as RAM on consoles is very limited you can't keep a lot of that data in memory so you have to load each section of the world as you look at it.

This makes IO performance veery imortant for RAGE now the PS3 is known to use 2 main weaknesses which is the slow read times of the Blu ray and also some issues with the HDD formating which limits the advantages of the HDD and also the limitations of the partitioned RAM which makes memory mangagement an issue when you have very large data sets. This leads to texture pop in being a slightly bigger issue on PS3 than a fully installed 360 version which can use the faster HDD IO and full install to reduce texture load times. Now RAGE on PS3 does use something to mitigate these issues by using the CELL to transcode textures faster but there is only so much difference that can make.

It will be interesting to see how the tech performs in the 30fps enviroment of Doom 4 as that will give the engine twice as long to load in texture before rendering the next frame so there should be far less pop in in that game. Alternatively if you used an SSD in the PS3 that could improve the pop in issues a lot, but they are expensive.

As for the PC version well that is just a bad port as by default the game only uses 600MB of RAM to cache textures even if you have a system with 4GB+ RAM. Add in the generally poor OpenGL drivers compaired to Direct X and you get basically the same performance as the consoles at a higher resolution which to a PC gamer is horrible. The fact that AMD put out the wrong driver at launch didn't help ether. The next patch should make the PC version much better looking tho with the new texture upscalling which will aliviate the blurry textures.

Interesting read, one of the things that troubles me is people forget that in the case of 360 the HDD is not universal and it would also be interesting to know what percentage of people on 360 actually install the game , but the tech reviews are never undertaken on say , one with no HDD ,one installed ,one uninstalled , I understand why but it would be nice  to see the differences. Concerning the HDD there shouldn't be a major difference after all the PS3 uses standard 2. 5"  laptop drives, I remember Sony talking about lack of memory for PS2 not being so big an issue  because it could swap memory in and out real fast because it had big fat pipes and used that same mantra again with the PS3, if this was true you would think mega texturing would be right up it's ally ,then again we live in the real world, I like many had high expectations for this tech especially it's low memory benefits, Simply put Rage was probably the wrong type of game to show it off apart from the Framerate side, and yes your right bring on Doom 4  at 30fps , I wonder what the people on here who  think that 60fps on console and it's attended short comings is better than 30fps and cleaner graphics think of that decision , looking back I have come to the conclusion  that like many Multiplats you can get to your baseline easier on the 360 and end up good across the board with PS3 you can get results in certain areas that equal or better the 360 but not across the board and not so easy and not when you have to maintain a certain parity not just game wise but time and resources wise after all its a multi platform engine, if you wanted the best outcome especially for the PS3 you would have them make two separate dedicated engines each built from the ground up for the  two platforms.