Comparing RAM usages in consoles and PCs

[Mobius1aic]

I was thinking of this as I was messing around with the CryEngine 2.0 sandbox. I was wondering about how RAM is used in consoles vs PCs. I'm assuming PC games store the same video data that's being used in the VRAM at that exact moment on the system RAM as well judging by the 1 GB of RAM being used (effectively 2 sets of data) while still storing sound/video/geometry data that's in cue to be used at a later point. On a system like the 360, are the same pieces of data only stored once since the RAM is unified and can be coded to metal anyways? Also I guess the PS3 would be used in the same manner despite the split RAM pool? I know this is alot of questions but they make me ponder, whether devs use this or that amount for video, this amount for other stuff, and whether or not data compression is used to give their teams more headroom. Basically I'm hypothesizing that PCs are coded to store all memory needed for the time being on the RAM, with data needed now for a current frame building being copied to VRAM therefore creating 2 copies of the same bit of data as where on a console you don't have that kind of room, you move data off allocated SRAM, move to framebuffer, render, move off of framebuffer. No coping, just "cut and past" if you will.....

Then as far as a needed framebuffer goes, where does the 360 stand in terms of needs? I know it could use the entire 512 MB of RAM for video if needed, but in reality is it on a similar level as the PS3, in the 256 MB range or even more? Realistically I can't see Xenos ever needed more than half the 512 MB UMA as a framebuffer.

 

[pc999]

On the PC you need to have all the things in the main RAM, then you need all the stuff that GPU will use in the VRAM too (duplicated). (unless you use a integrated card or turbo memory like?)

On PS3 both the GPU and CPU can acess both RAM pools so you dont need to duplicate.

On tth e 360 there is only one pool, so no need to duplicate anything plus 10MB of Edram for framebuffer ops and the such.

 

[T.B.]

On the PC you need to have all the things in the main RAM, then you need all the stuff that GPU will use in the VRAM too (duplicated). (unless you use a integrated card or turbo memory like?)

Well, for OpenGL that is true (and I think for D3D10 as well). For D3D9, only objects in the managed pool are shadowed by host-memory copies. That's why you don't need to recreate them when you lose the device.
One good reason to have most of your resources in the managed pool.

 

[Mobius1aic]

That's what I figured considering you have multiplatform games that on the PC use 1 GB or even more of SRAM, but of course you're talking about possibly better graphics as well as prevention of data transfer hiccups.

 

[Blazkowicz]

the X360 could make use of 1GB ram, imagine if both consoles had double the ram : id's Rage would be tailored for that and have higher res textures overall. Consoles typically are memory starved while high end or recent PC can't make use of all their ram on a game.

 

[Mobius1aic]

the X360 could make use of 1GB ram, imagine if both consoles had double the ram : id's Rage would be tailored for that and have higher res textures overall. Consoles typically are memory starved while high end or recent PC can't make use of all their ram on a game.

This is nothing new. I think most consoles are pretty memory starved, and devs have to come up with innovative solutions to get what they want out of the system without compromising quality enough to kill a good product.

 

[Graham]

the X360 could make use of 1GB ram, imagine if both consoles had double the ram : id's Rage would be tailored for that and have higher res textures overall. Consoles typically are memory starved while high end or recent PC can't make use of all their ram on a game.

It's all tradeoffs. Every system has to be balanced for cost and performance. If the xbox had 1024mb of ram, then you'd just be limited by other bottlenecks instead - such as how fast you can fill that memory. If you are limited by all bottlenecks at once, you have a well balanced system

Anyway, that's a bit off topic.

 

[Shifty Geezer]

If you are limited by all bottlenecks at once, you have a well balanced system

Well balanced, but underpowered . Gimme a limitless console!

 

[Iron Tiger]

It's all tradeoffs. Every system has to be balanced for cost and performance. If the xbox had 1024mb of ram, then you'd just be limited by other bottlenecks instead - such as how fast you can fill that memory. If you are limited by all bottlenecks at once, you have a well balanced system

Anyway, that's a bit off topic.

Take the Gamecube as an example. A reportedly well-balanced console that, in the Wii, got a 1.5x boost in clocks, but a larger increase in the RAM pool. But we're not really seeing the fruits of the RAM increase. It would have probably made a much bigger difference to increase the EDRAM size, to buffer the higher res screens the faster GPU could potentially draw. Or cache larger textures from system memory.

 

[DuckThor Evil]

Gimme a limitless console!

Your parents probably didn't have it easy during christmasses

 

[Neb]

Well balanced, but underpowered . Gimme a limitless console!

Buy a PC.

 

[Shifty Geezer]

Buy a PC.

Unlimited's no fun when the price-tag follows the same principle

 

[Neb]

Unlimited's no fun when the price-tag follows the same principle

Touche.

 

[Silent_Buddha]

Unlimited's no fun when the price-tag follows the same principle

That's why you lower the temperature to 0 degrees kelvin, hook it up to a nuclear power generator, jackup the voltages and overclock it to infinity...

Or watch it blow up. Either way would be tons of fun...

Regards,
SB