Apple TV "single core" A5 actually has two cores, one is off
chipworks.com
chipworks.com
Intel sold 486SX and 486DX parts - the latter had a built-in floating point unit, whereas the former did not. Or at least that's how they were sold. If you had the SX, you could get a 487 "math co-processor" as an add-on to get your floating point unit.
As it turns out, the 486SX, 486DX, and 487 were actually the same chip, with different functionality enabled (although I think the 486SXs were actually ones with defective FP units).
Anyway, if you upgraded your 486SX with the 487, really what happened was that your 486SX got disabled completely, and the 487 became your one and only processor, with a FP unit.
[EDIT: typo]
Original Xbox used marginal DRAM chips and detected by software on each boot which regions of memory are actually usable.
AMD's current CPUs with "weird" number of cores (3, 6, 12..) are produced by disabling cores that does not pass tests.
Cell BE as used in Playstation 3 has one SPU disabled for same reason.
While in most cases such disabling is done by blowing some fuses in hardware I can imagine that in embedded systems software only solution (like the Xbox one) is actually more convenient.
Celerons were originally Pentium IIs with large segments of the cache fused off, unusable due to defects. However they turned out to be so popular that Intel started to disable the cache of otherwise good cores, and then later began specifically fabbing them, to meet the demand.
That was a time when hardware, particularly memory, was expensive. This was in 1982.
Interestingly, Intel now offers "upgrade cards" for low-cost CPUs whereby components are deactivated via firmware or suchlike and special codes can be entered into the bios screen to turn them on (for a price, of course).
http://www.team5150.com/~andrew/carmack/johnc_interview_1997... (search for "float")
A Pentium 75, perhaps the slowest Pentium ever made, was at least ten times faster because of the floating point gains.
It's loud, it's slow, the UI is pretty bad and unpolished. Sometimes it boots to a black screen or locks up randomly. Heck, 1 out of 5 times it doesn't even shutdown (just hangs on a black screen infinitely).
These are all documented issues (and really only the tip of the iceberg) that have gone unfixed for years.
Either Apple is only utilizing one core or they are binning parts
So, there are possibly two cores, but it's not confirmed.
"Binning parts" means they're either actually hardware-disabling ("diking out") the extra core, or the extra core was bad to begin with (making use of otherwise bad chips).
If those images are real, both cores are definitely on the chip, but whether one is hardware-disabled or not is not certain.
It does seem like the images are real, because apparently the site is in the business of selling very high-res versions of such chips:
http://www.chipworks.com/en/technical-competitive-analysis/r...
"Die photos are available in the Chipworks Report Store at top metal and lower metal/poly"
Sadly, it's one of the few semiconductor segments in which Ottawa, where I live, is still something of a leader.
And, weirdly, the owner of the company used to live in the condo below me.
The simplest and most plausible explanation here is that they're using the Apple TV's relatively low performance demands as a way to get some use out of A5s with defective cores
It makes sense to me that Apple is testing out yields for the next iPhone. This new, smaller manufacturing process will allow Apple to put LTE in the next iPhone by having the CPU take up less space and consume less power.
I don't envision a speed bump to the Retina iPad this year. Rather, I expect the iPad to be revised again next year. It should be on the new, smaller manufacturing process, but I'd expect the new iPad to be ARM A15 based, not A9 based like Apple's current iOS products. The next iPad may have double the CPU power while also getting better battery life.
In fact, with the new GPUs that Apple will be using next year and the new CPUs, I expect the next iPad to be more powerful than the XBO 360 and PS3. That'll be a very interesting day for gaming.
Then double that for the old iPad2s.
http://blog.macsales.com/9102-secret-firmware-lets-late-08-m...
Either way, that isn't what is happening here. This is just CPU manufacturing 101. New chip, new processes, high bin rate. You mitigate this as much as possible by disabling features on binned chips to make them sellable. Intel has done it a number of times, typically when making a big change like the introduction of the Core Duo.
"You're making us lose business by providing a tool to allow customers to use more than what they expected and paid for."
It's not necessarily a "social good" to provide tools like this. It obviously annoys nerds to no end that companies use software to detune hardware for price segmentation; the nerd worldview is, "what hardware you sell me is mine to do with as I please".
That's utterly sensible. But in the long term, it means that either consumers will have to pay more, or that companies will have to waste time specializing hardware to perform the same segmentation goals. In other words: it's a win for a tiny minority of hardcore nerds, but a loss for everyone else.
Also: consider carefully that similar techniques are used throughout many different industries. For instance: recreational boat engines are detuned in software to provide multiple performance categories at different prices.