brilliant Lee Bradley pointed me towards the two sets of figures that are causing plenty of debate.
VG247 is reporting that the PS4 will have 1.84 Teraflops of computing power thanks to an AMD A10-based APU, and that the next Xbox will have 1.23 Teraflops of grunt thanks to an AMD Radeon HD 8770 graphics chip.
NowGamer reckons the next PlayStation will have "an APU with a fast GPU" that'll have 3.2 Teraflops of power, but the Xbox will outstrip it with 4.2 Teraflops delivered by three System On Chip units working together.
VG247's story sounds plausible, but NowGamer's is wide of the mark. Here's why.
It's long been rumoured that the PS4 will be built on an APU, and it's easy to see why Sony wants to go down this route. AMD's APUs, or Accellerated Processing Units, combine a processor and a graphics core onto the same chip, and I've previously praised them for offering reasonable application power and good gaming ability at low cost.
AMD's current top-end APU is the A10-5800K, which includes a Radeon HD 7660D GPU. The graphics core uses the same naming convention as AMD's current discrete cards, but it's based on the architecture behind the older Radeon HD 6900-series. The HD 7660D has 614.4 Gigaflops of power, while the whole chip has 736 Gigaflops.
That's a country mile behind the 3.2 Teraflop figure that's doing the rounds.
AMD has announced the successor to the A10-5800K, so it's plausible that Sony might use hardware based on the A10-6800K in its next console. The new part's GPU will apparently be based on the forthcoming Radeon HD 8000-series graphics cards.
Bear in mind that the HD 7660D GPU was based on the HD 6900-series, and then look at this chart: several high-end 8000-series GPUs, apparently designed for OEMs, bear the Tahiti codename, which debuted in the HD 7970 and HD 7950. It's hardly a stretch to see AMD recycling last year's discrete graphics cards into this year's APUs.
Plenty more evidence suggests the 3.2 Teraflop figure simply isn't anywhere close to reality. If true, it'd put the PS4's graphics core smack between the outputs of the recently-leaked Radeon HD 8870 and 8850. However, those two cards have TDPs - Thermal Design Power, or the maximum power draw of a chip - of 160W and 130W on their own. That figure doesn't take into account the power needed by the processor, and reports have said that the A10-6800K as a whole will have a TDP of just 100W - the same as the A10-5800K.
AMD has traditionally cut down its GPUs in order to fit them inside APUs. The HD 7660D inside the A10-5800K may have been based on 6900-series cards, but it included just 384 stream processors. Even the most modest of those discrete chips, the Radeon HD 6930, included 1,280 stream processors and had a 186W TDP. The HD 6970 had 1,536 and a 250W TDP.
There's no way an APU could contain a graphics core of that power while also packing in a processing module too: the power requirements don't add up, and the heat generated would be too much for a console to bear. There's a reason discrete cards, with more than 1,000 stream processors, are sometimes nearly a foot long, while the 384-stream processor APU can be contained in a single die alongside a CPU.
Another major concern is cost. The A10-5800K launched at £100, and there's no reason for AMD to deviate from this blueprint for the A10-6800K - low cost is one of an APU's big advantages. To find a discrete AMD card that launches for that price, you've got to go a long way down the range. The HD 7850 cost £190 new, the HD 7870 was £275, the HD 7950 was £340 and the HD 7970 was £432. Even now, they're not much cheaper: around £150, £200, £250 and £320 respectively.
Sony might price the PS4 highly for the console market, but that level of GPU is way out of its league. Sony would be able to buy the cores for cheaper than retail prices, sure, but it's also got to factor in the rest of the APU, memory, storage, a motherboard, a Blu-ray drive and a high-end case - as well as its profit margin.
Conventional desktop PCs that use the A10-5800K rarely cost less than £400, so it makes sense that Sony - saving money using its own manufacturing facilities as well as its buying power - would build its next console around one of these more modest parts. Last year's APUs are good enough for console-level gaming; I've no doubt that next year's APUs would get the job done, too.
It's arguable that producing the world's best APU and giving Sony exclusivity would be an awful economic move for AMD - a company that's not having the best of times when it comes to finances. And it's not as if Sony's got the cash to buy AMD's exclusivity, either.
After all, why should customers buy any of its forthcoming discrete GPUs if Sony is selling an entire console that's just as quick for little more than the card alone would cost, and how would customers react if its best APU wasn't available to build inside PCs?
AMD's hardware partners would be up in arms about it, too - they'd presumably want to stuff the chip inside laptops and desktop machines. Its graphics card partners would want to know why AMD was ruining their sales for the sake of a console, too.
The 4.2 Teraflop figure for the Xbox 720 is similarly silly. NowGamer says the next Microsoft console will be based on three SOC modules, with one based on the Radeon HD 8850 GPU and two using HD 8900-series cores.
Even downclocked, the combined power could be enough to hit that mythical 4.2 Teraflop figure, but I still don't reckon it's plausible - again because of heat and cost.
These high-end cards are traditionally some of the largest around, and leaked information suggests that 8900-series OEM parts will have TDPs of more than 200W, with the HD 8850 coming in at 130W. NowGamer's article reckons that Microsoft's cut-down cores will see the machine having a 300W power brick, which trumps the 175W brick included with the Xbox 360.
If these rumours are true, that's one power-hungry console. And then there's the price: last year's HD 7950 cost £340 when new and, while there's no way Microsoft would pay that for each GPU, consider that it's allegedly putting three graphics cores into its next console. Then consider the cost of every other component, and Microsoft's slice of profit margin.
That would make the Xbox 720 one of the most expensive and power-hungry consoles ever made and, given the hardware that's allegedly being used, it'd be one of the biggest and loudest ever, too. Considering the Xbox 360's reputation, I'm not sure that's what Microsoft wants to do.
Are any rumours right?
VG247's figures might be less exciting, but they're far more realistic. It's hardly a stretch to imagine the PS4 using a modified A10-6800K APU and, again, it's reasonable to speculate that the GPU inside will be a tweaked version of an HD 7900-series core. The discrete chips in that range run at between 2.8 and 3.7 Teraflops, so a low-power version running at 1.8 Teraflops - in order to fit inside one chip, and to remain cool inside a console - makes more sense.
It's also worth remembering that consoles use processing power more efficiently than PCs, so clever coding will make up the shortfall between theoretical power and actual visual output.
VG247 says the next Xbox is based on the Radeon HD 8770, which is a forthcoming mid-range part. No power figures have leaked for this chip but the corresponding part in last year's range, the HD 7770, hit between 1.2 Teraflops and 1.4 Teraflops, and it had a reasonable TDP of 80W.
Microsoft can take the HD 8770 and cut it down to size to hit its rumoured 1.23 Teraflop figure, which is a move that seems sensible. The HD 7770 has enough power to play most games at 1080p already, and the HD 8770 will be better still. Why do more?
It's easy to get caught up in speculation when talking about new consoles, but it's worth tempering rumours with a healthy dose of reality. AMD cramming a graphics core that's faster than its best discrete cards into an APU that's cheap enough, frugal enough and cool enough to run inside a console is a flight of fancy.
Similarly for Microsoft: producing three SOC products, each with its own high-end GPU, makes little sense when an extremely capable single graphics core would do the job just as well and for a lot less cash.