AMD Downgrades Bulldozer Transistor Count By 800 Million 149
Robadob writes "It has come to light that AMD PR had originally reported that the new Bulldozer processor's transistor count was 2 billion. AMD PR are now asking reviewers to correct this count to 1.2 billion from the original amount they provided ~3 months ago."
Serious policy changes here ? (Score:3, Interesting)
Normally the route of a true american corporate cultured corporation would be to deny everything and fool everyone and rip as much cash as it can. Until they were confronted at courts.
But now, amd marketing is rather needlessly contacting reviewers to make corrections, while taking a hit in p.r.
But is it really a hit ? Coupled with the fact that the new ceo kicked a lot of marketing staff, this tells me that the new term in amd is going to be a term reminiscent of early 90s in technology - a responsible era in which corporations have actually manufactured useful gadgets and sold them honestly, trying to get the edge on each other through tech - not with filthy dealings or deceit (hello intel and the bribery verdict)
Why? (Score:5, Interesting)
What's the true relevance of transistor count? If I see two processors with identical performance and power efficiency but radically different transistor counts do I have any real world incentive to select one over the other? I mean, presumably the one with fewer transistors in roughly the same die space might overclock better, might have a longer MTBF, etc., but beyond that should I care?
Or did timothy post this just to keep up the fanboi flame wars?
Re:Why? (Score:5, Interesting)
Re:Why? (Score:5, Interesting)
Or maybe 2billion is what the thing actually has, but in order to get it to work they had to abandon a significant portion even if they still exist on the chip.
It wouldn't be the first time unused banks of memory were left on chip but simply abandoned.
Class action lawsuit please (Score:3, Interesting)
There's a new update (Score:4, Interesting)
AMD just clarified that Bulldozer does have 2 billion transistors after all, but only 1.2 billion work. Which explains something about its performance.
Re:Why? (Score:5, Interesting)
What's the true relevance of transistor count? If I see two processors with identical performance and power efficiency but radically different transistor counts do I have any real world incentive to select one over the other? I mean, presumably the one with fewer transistors in roughly the same die space might overclock better, might have a longer MTBF, etc., but beyond that should I care?
If you can find one processor with 2 billion transistors, and another with 1.2 billion, and they both draw exactly the same power requirements, performance, instruction set, and have the same heat envelope, then either somebody in marketing is lying, or somebody is doing something horribly wrong. On the one hand, it should not take 2 billion transistors to do something that can be done with 2/3 of that, but on the other hand, if you have 1/3 fewer transistors, you should experience an according decrease in heat leakage.
That being said, numbers like transistor count matter to enthusiasts. These are the same people who used to spend $1000 to buy the 3.8GHz P4 chip instead of the $300 3.4GHz chip. For some folks on the market, bigger == better, and there's no point in trying to explain to them that they can accomplish the same job with a less powerful chip. Some people build/buy/upgrade computers so that they can brag about being more powerful than their buddies, and when you couple that mentality with a disposable income, well, you know the rest.
For somebody like me, it's not likely to make a big difference. But I'm typing this on a laptop that's powered by a Celeron U3600 ULV chip... a dual core 1.2GHz processor that's designed for low power consumption, not high performance. It's been a long time since I have built/bought a high performance system, and I'm unlikely to get back into that game for a while: I gave up on computer gaming years ago. The one thing in this announcement that may give me pause next time I build a system is that a revision from 2 billion to 1.2 billion transistors probably means some kind of manufacturing problem that they thought they could overcome, but are now not thinking they can. Even if that's not the case, AMD is going to have egg on their face a while over this one.
Cache? (Score:4, Interesting)
I recall seeing that the top Bulldozer only had 8MB L3 cache, which seemed a bit low - Intel's equivalent top-of-the-line desktop models reach 15MB, and the server models 30MB.
At first, I just figured they were targeting the middle price bracket, but then they priced against the high-end. So I would not be surprised if much of the missing (or disabled, if that rumor turns out to be true) transistors belong to the cache.
Re:Why? (Score:4, Interesting)
IANALE (I am not a layout engineer), but it's my understanding that it is not an easy task to actually figure out how many transistors are contained within a modern chip. The CAD tools used aren't anything like Photoshop, where you can pop up an info window and see how many pixels it has.
Actually, it is really easy to figure out how many transistors there are. Generally, you run both LVS (logic vs schematic) and DRC (design rule checking) tools on the final layout data base. These tools look at all the transistors in the layout data base and compares them to the original design (LVS) and to make sure that the active areas of the transistors are spaced out accordingly to make sure they can be fabricated into masks that yield (the base rules are provided by the silicon foundary often augmented by the library provider). After you run these tools, AFAIK it just tells you how many transistors it checked. You might tell the tool to skip some parts of the design (say like rams) in the final netlist, but generally the parts you skip have been run through the tools before hand or in parallel.
Of course running these tools takes a long time, and sometimes they are not finished running before the chip is fabricated for the first time. Sometimes, you send off the design or tape it out, and then you kick off running these tools so the chip starts to go to the mask-maker whist you are still running the LVS/DRC tools, but generally you know the results of LVS/DRC before you go into production (or your company probably isn't meeting your ISO 900x certification requirements). If nothing else, the fab will make you sign a yield waver if you don't run DRC (basically, they won't guarantee any working parts).