| DM235 said: Anyone else here familiar with AMD architectures? I understand how SemiAccurate came up with their prediction of a 1.9 GHz clock based on the transfer rate between the Northbridge and the DRAM Controller, and the assumption that the CPU must run at a fixed multiplier to the Northbridge clock. Ethomaz believes that the CPU could run at an arbitrary multiplier to the Northbridge clock, but I cannot find any documentation that says so. |
That's because there isn't any documentation or whitepapers released by AMD that would verify such claims.
However, what they are basing it on is the fact that Jaguar is an evolutionary step from AMD's Brazos, both CPU's have more in common than what is different at an architectural level.
Still I wouldn't mind knowing some of the more intricate details of Jaguar/Kabini/Temash, just such details are light at this stage.
What AMD did do with Jaguar however is overhaul the North Bridge, whether they changed things up more for the consoles remains to be seen and no one will know that untill solid information becomes available.
In the end however, the Xbox One's CPU will run 18.75% faster than the PS4's CPU (If that does indeed run at 1.6ghz and if these rumors prove to actually be true for the Xbox One), however one thing to keep in mind is that performance generally doesn't scale linearly with increases in clockspeed anyway.
The other take from it is, the Playstation 4's GPU is far more powerfull than the Xbox One, that it wouldn't matter if they lost CPU performance to the Xbox One, they would be able to offload CPU compute time to the GPU anyway, provided the tasks are highly parallel of course.
The next generation CPU's like this current generation are still going to be horribly slow, just with each new generation the CPU is simply less important, only so much you can do with a 2-issue design from a performance perspective.
Captain_Tom said:
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Even though the consoles have 8 cores, it's still not going to be faster than say... A Core i3 Dual Core.
| ethomaz said: Northbridge clock runs synced with memory clock... not CPU... you can change it in APUs for any value (NCLK in BIOS). "The NorthBridge typically trails the memory clock (not to be confused with data rate); for example, at DDR3 1333 with a memClk of 667 MHz, the NB Clock (NCLK) will be running at the next lower divider clock, in this case 654 MHz, at DDR3 1600, the NClk will increase automatically to 800 MHz and so on. Since the A series natively supports memory data rates of up to 1866, the NClk is unlocked in all A-series APUs." |
Not always.
AMD and Intel have a Reference/Base clock (Typically 200mhz) which allows the CPU and North Bridge to be untied from the memory clock speed and thus allows you to increase clockspeeds with a mere increase in the multiplier or "Base clock" without touching on the Ram.
If you tie all the clocks together and lock them, then overclocking the Ram will overclock the rest of the system.
Microsoft would be able to increase the multiplier without much effort.
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