Melcar

ATI already did the 512bit thing. The result was a huge, power hungry core with more bandwidth than it could ever use. The bigger bus does increase price, and right now AMD is trying to be more efficient with its economics. As for performance, we will see which approach is better once the cards come out and comparissons are made.

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RayvinAzn

I didn't claim to be anything, you seem to hold yourself in very high regard for going to college, something that is on the same level of achievement as tying your shoes in the morning. And I'm not going to start arguing about grammar and spelling (since those aren't what I was talking about in the first place), but yours is far the exceptional. And to quote the American Heritage dictionary, a paragraph is "A distinct division of written or printed matter that begins on a new, usually indented line, consists of one or more sentences, and typically deals with a single thought or topic or quotes one speaker's continuous words." Five sentences about a single topic certainly seems to qualify as a paragraph. I probably could have been more precise, but I doubt there is anything in there that is indicative of a run-on sentence.

So, in your humble opinion a 512-bit bus is better than faster RAM. Care to say why? Are there any actual advantages to it, assuming memory bandwidth being the same? You keep saying that GDDR5 is too expensive and shouldn't be researched, but why not? I'm sure both Nvidia and ATI have no problem researching how to make a 512-bit memory interface, there's no real advancement there. Getting a new type of VRAM is at least a technological step forward, not only from an engineering perspective, but from an R&D one as well. You say that GDDR5 hasn't been proven yet - neither has a 512-bit memory interface either, unless you consider the HD2900 series a resounding success.

And yes, of course they would stick to a 256-bit memory interface on the lower end, but how would that affect compatibility between the chips in Crossfire? I honestly have no idea if it would or not, but it seems to me that a large architectural difference like that could lead to problems, or at least keep costs higher on the lower-end, since the cards had to be designed for a 512-bit memory interface, then scaled back. Switching the kind of RAM used seems like a fairly easy and cheap way to instantly create a low-end card.

And why wouldn't a more complex PCB contribute to heat? Double the amount of traces, that's more electricity that has to go more places, which is going to add to the overall heat output of a card. Not as much as the GPU itself I'm sure, but certainly more than using a different type of VRAM.

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killnine

Welcome to the club of EEs.

The bottom line is that it isnt cost-effective to solve the bandwidth problem twice. ATI doesn't need both GDDR5 and a 512-bit bus. It is as simple as that. There have been plenty of reports coming out that state until ATI can integrate their DDR5 solution, they will use a 512-bit bus with DDR3 to keep the memory bandwidth high. Later, they will likely use DDR5 and use a 256-bit bus to reduce die complexity and increase yields during manufacturing.

My guess is that a higher bit width doesn't directly correllate to higher temperatures because of the PCB or anything (see: I agree with you). However, I would say that using a 512-bit solution is a far more complex architecture (see: R600) and therefore requires more logic on die. The result? A more power-hungry chip than a 256-bit counterpart.

The bottom line is that I dont know what ATI is going to do for sure, but most signs point to the fact that ATI will choose one, not both, solutions for memory bandwidth.

You have stated yourself that you are a electrical engineering student. Good for you, but that typically means you are on the receiving end of practical design knowledge, not the giving end. So sit back and chill out, this is all speculation anyway.

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QuickS

They are using a 512bit bus though, so obviously AMD/ATI thinks otherwise.

RayvinAzn

I have yet to see this confirmed. I've heard that the GDDR3 might use a 512-bit memory interface to make up for lack of bandwidth, but never seen if really and solidly confirmed (and it seems to me that the whole point of the GDDR3 cards is to be cheaper, and adding the 512-bit bus will make them more expensive all over again), and I've seen people misinterpret a dual-GPU card like the HD3870X2 as having a single 512-bit memory interface where it actually has two 256-bit interfaces, but we don't know for sure what sort of interface the HD4k line will actually be using.

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binormalkilla

EXTREMELY misleading title.......the article doesn't provide a single benchmark result.