Tetrium wrote on 2022-02-18, 10:00:Regarding the K6/K7 thingy, I don't really understand why AMD even made the K6-2+ in the first place, unless AMD could disable p […]
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Regarding the K6/K7 thingy, I don't really understand why AMD even made the K6-2+ in the first place, unless AMD could disable part of the cache to sell off partially defective K6-3+ chips as K6-2+ chips. If this ended up actually happening is the question though as yields seem to have been really good.
K6+ was in my eyes clearly made for the laptop market. K7 was a power hog compared to K6+ and in laptops battery duration is all important to drive sales.
Perhaps K7 could actually be clocked lower, but it's conceivable that to reach K6-3+ 400 ATZ 1.6v power dissipation, Athlon would need to be clocked to such a low amount of MHz that this would hurt sales (because who back then would want to buy a (just pulling this out of my magic hat for a bit for explanatory reasons) 200MHz Athlon if a 400MHz K6-3 sounds faster (or Athlon would need to be clocked higher with the battery lasting less long as well?) and it's probably also cheaper on the chipset side. K6 was also old tech at the time, perhaps being more reliable, cheaper and easier to implement in laptops.
It was all about the megaherz back then, IPC didn't really exist as a concept at the time.
Deunan wrote on 2022-01-28, 11:29:AFAIR the III+ chip dies were considerably bigger due to having extra cache on them, that would typically result in more load on […]
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majestyk wrote on 2022-01-20, 07:57:
Chances are that AMD followed a price discrimination policy and sold faultless "castrated" III+ chips as 2+ to meet the demand for cheaper mobile CPUs.
I´m not sure if I remember this correctly but didn´t a larger cache (in the same CPU) mean a lower maximum CPU speed?
AFAIR the III+ chip dies were considerably bigger due to having extra cache on them, that would typically result in more load on the internal signal paths so extra latency cycles were added to help with that. Depending on how it was done, and manufacturing process limitations, you could either get extra latency but higher clocks, rarely same latency with higher clocks, often same latency/clock or even regression but made up for by the cache being larger now.
Point is, there is no reason AMD (or any other chip manufacturer) would cripple their best dies, expensive to make on the best process available, to sell them as parts with lower margins. Not even Intel was that rich and stupid, except when the dies were so easy to make it wasn't much of a loss to rebrand them. AMD at that time had it factories running 24/7 to meet demand and they wanted to sell the latest and greatest Athlons for big bucks. I just don't see someone making an insane decission to forget that, make more III+ cores instead of Athlons and then rebrand them as 2+ to sell at lower price.
As I see it, the only III+ cores that would be rebranded to 2+ (if any) were either defective cache dies or didn't meet other specs (clocks or power draw at rated speed). Now, it might be possible to find a part that is fully functional, and can somehow be unlocked to full cache size, but will require more juice to run and will generate more heat. But that would be like winning a lottery ticket I think. But, good luck, I just hope you people won't kill a ton of 2+ chips trying to delid them to find that one III+ core.
One reason a CPU company would want to do this, is to flood the lower segments with cheaper CPUs to harm CPU sales of your main competitors. Intel kinda did actually do this and other companies probably did something like this as well.
Well it was not literally their very best dies, but they certainly did sell better parts underclocked for a lower price than it was arguably worth at the time, just to be as much of a hindrance to their competitors as they could.
Because of their competitors made less money, they would be less able to invest in faster CPUs and be less of a competition, indirectly increasing revenue.
Yes, they were certainly intended to keep a foot jammed in the door of the mobile market while a mobile Athlon wasn't ready. The argon, pluto and orion cores were unsuitable for power reduction, and at the 500-600 Mhz level mostly performed on a par with the K6-3+ due to having baked in pipelining and timing designed for higher speeds, kinda like the 286-16 386-16 thing. So there was no point clocking them further down. Thunderbird came along, and while it was good enough to push the clock speed on desktop, it wasn't quite good enough to get acceptable mobile power figures. The next stopgap as it were was the cache trimmed version, the Duron Spitfire core, which could with the hot running cache reduced, be made into a mobile model to patch the gap from 550 to 1Ghz. It wasn't until the Palomino core that a "proper" Athlon mobile existed, and maybe you can see how much they felt this mobile deficit, by the fact that palomino wasn't released on desktop, it was only available as mobile CPU for a number of months.
Where are they all? You might ask of the K6-2+/3+ laptops, or even the early Duron ones. Well I think the cap plague applied much slaughterage to the population in the wild, and also what I call the "everybody forgot how to make hinges" problem. Which is really a story of how you can't make mass market consumer priced laptops with a full magnesium alloy frame that you had in the 90s $3000 business models. So cheaper materials and lower part count in the consumer laptops had screens snapping off left and right, until they figured out how to do cheap and reasonably durable, or found the floor of the absolute minimum you could get away with. Which was actually the ceiling above what they were trying to do in 99-01. Another factor to that is that screens had got bigger and heavier, a little 9" didn't cut it any more, ppl wanted full 14", 15" panels which were quite heavy up to around late noughties when they began to get slimmer and lose mass.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.