Next Gen Question

[Gamingphreek]

With all the next gen video cards on there way to mainstream, this leaves some questions. I was wondering, why didn't ATI or Nvidia incorporate a 512bit memory bus. Is it possible... Wouldn't that double the bandwidth that is needed so much by the video cards.

This would have definately put one of the two of them ahead, but it would have increased costs. But nonehteless is there any reason why it isn't incorporated. Same goes for a 512bit GPU.

-Kevin

 

[Ages120]

They already got 256 bit GDDR3! To expensive, to hard to implement, they are already way ahead of system memory. I think they did an awsome thing this time around for memory. Breaking 1ghz while still keeping very cool. They will get there in 18 months most likely.

 

[azel]

It's possible but double bandwidth means more than double wiring and double the cost.
Not only wires but gates must be increased. Memory storage must be larger.
Double wiring leads to double space, and there are significant space constraints in IC design.
...Not to mention power usage and heat generation increase.

But technical difficulties can be overridden with enough money.
The reason no one go for such high precision GPUs is because they won't really make things fast.
A 256-bit GPU is not "faster" than a 128-bit GPU; it just does more precise calculations.
Unless numbers being dealt with are more precise than the GPU, the GPU must take extra cycles to do one operation.
Yet no current gaming software or standard use 512-bit numbers.
A 512-bit number has approximately 150 digits in decimal; even astronomical values require less precision.

As for just having a 512 bit memory bus, it's like having a 8 lane highway in farmland; there's no traffic to fill it up unless the GPU processes much larger numbers. Having 2 256 bit busses will be much more help.

 

[Genx87]

They are taking the approach of increasing raw memory bandwidth along with compression algorithms on the GPU to boost effective bandwidth way beyond what the raw bandwidth is.

Someday they will probably have to move forward to 512bit bus but it is expensive with current technology.

 

[Cerb]

Why are the SE models so much cheaper (not counting Powercolor's 9800SE)? Cheaper PCB.
512-bit would really suck--I doubt they could make the cards that way for under $300. They really aught to just do 128-but XDR-derivative, IMO.

Azel: they are 128-bit floating point for calculations in DX9. Period. The bits referred to are memory bandwidth. Current 256-bit cards have four 64-bit DDR channels.

 

[Pete]

Simple answer is probably because it's too expensive (size and traces) ATM. I'm guessing we'll see it with 90nm parts.

 

[caz67]

I read an article , that stated Nvidia will be releasing a 512Mb version in the future. When i find it ill post it for you.

 

[vshah]

Originally posted by: caz67
I read an article , that stated Nvidia will be releasing a 512Mb version in the future. When i find it ill post it for you.

we're talking memory bus width, not amount of ram..

-Vivan

 

[DSVxUltraGL]

512BIT wide mem bus is hard to implement and would skyrocket the prices of the cards, but it "actually" exists, pro gfx chip maker 3D LABS utlized it in there new Realizm 800 cards, and it ended up by costing over $3000+!!!.

NOTE:Realizm 800 is a dual vpu card, so 256bit for every chip.

 

[caz67]

we're talking memory bus width, not amount of ram..

Sorry misread the post.

 

[Goi]

512bit isn't economical currently. It may be in the future. Or we may move to embedded DRAM. But that technology seems to be dead in the water.