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The Handheld Steam Machine With Linux & AMD SoC Moves Ahead

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  • #31
    Originally posted by juno View Post
    On the official product page it still sais 4.0. I don't search deeper again now but all I know is I also checked some datasheet and it also said 4.0. Sorry if that info is wrong or outdated or they only said that because the drivers were not ready or whatever. If this is the case, AMD really should work on that. They should maintain something like Intel with their ARK
    Right... Here's the link from where I checked that:

    Basically the product brief says it pretty clearly on the first page that G-Series SoC's for embedded use support up to OpenGL 4.2. If you're going to start making stuff up, at least don't do it in a way where it's really easy to check if you're making it up or not.

    Originally posted by juno
    Just because the shader architecture is "GCN", the GPU doesn't have to support all the hardware features that are available on the desktop. You also don't have the same features available on a FirePRO and a mGPU, even if both are GCN, and I'm not talking about the cut-down fp64 performance.
    Of course they have time. But we are talking about that specific piece of hardware that they now advertise and that they now want to "sell".
    While there are some minor differences and the usual firmware sabotaging of fp64 performance to sell more workstation cards, they're still fundamentally the same architecture so there really isn't any reason why these things somehow couldn't support newer OpenGL-versions. On Windows for instance even a lot of pre-GCN cards support OpenGL 4.5, clearly showing that it's just AMD not bothering to implement driver support for these chips.

    Originally posted by juno
    Sure, but that's not what this is about. btw. I don't think that it is cheaper to build the exact same, but shrinked SoC in 14 nm at this time. Later, when the yields come closer to those in the planar 28 nm process it will surely be cheaper.
    As I said, it's not clear cut and in the early part of a new node's life is always the part where you have the most problems. We are after all talking about a device coming out next year, not something that'll come out in a couple of years when all the yield problems have been sorted out. Apple's already started shifting their purchasing more and more towards Samsung because of GlobalFoundries having yield problems with the 14 nm node.

    Originally posted by juno
    Sorry, that's just plain wrong. You totally underestimate the impact of architectural changes on performance and power efficiency.
    You must never have heard about Intel's Tick-Tock process? They release a new chip architecture (Tock), then shrink it (Tick), then a Tock on the new node, shrink it again (Tick) etc. The bigger steps in the younger past were always Tocks (Skylake, Haswell, Sandy Bridge(!)) while Ticks brought way less impovements (Ivy Bridge, Broadwell).
    Trying to sound smart by acting like I haven't heard of the way Intel's way of developing new chips by alternating between introducing a new microarchitecture and a new node? The last few rounds of that have been pretty disappointing to say the least. While the power draw isn't going anywhere, at least performance has been going up even thou it's always less than 10% per new microarchitecture. This is the reason why Intel CPU's hold their value so well on the second hand market and why I went with a second hand i7 950 while I wait and see if Zen is any good.

    Originally posted by juno
    Also, the TDP for AMDs FX-CPUs or APUs did only rise when they raised the frequency a lot. And I mean a lot. You have to keep in mind, that FX-CPUs only saw the first two of four bulldozer iterations. And the clocks went higher, even if the TDP remained stable.

    Zambezi (1st gen bulldozer): FX-8150 w/ 3.6-4.2 GHz, 125 W
    Vishera (2nd gen bulldozer): FX-8370 w/ 4.0-4.3 GHz, 125 W; FX-9590 w/ 4.7-5.0 GHz, 220 W
    Of course, the Vishera were also faster and still more power efficient for the same clock speeds compared to the Zambezis. All of these are in GlobalFoundries 32 nm SOI, btw.
    Same is for the APUs:
    LLano: 3 GHz, 100 W
    Richland: 4.1-4.4 GHz, 100W
    [Kaveri: 3.9-4.1 GHz (ofc still faster), 95 W] <- this one is in TSMCs 28 nm instead of GF's 32 nm process.
    [Bristol Ridge: ??? yet to come]
    Probably shouldn't have spoken about the official TDP rating, but instead actual power draw because those figures can vary pretty wildly with chips with the same official TDP.

    Just look at the fx-8370 and 8350 which officially have the same TDP:

    Originally posted by juno
    As we are already way too off-topic, I'm not going to explain to you why Hawaii was and is actually an efficient GPU and why it has the reputation to be a like you call it "mini furnace".
    I'd hardly call consuming over 100W more than a Titan Black very "efficient":
    "Why should I want to make anything up? Life's bad enough as it is without wanting to invent any more of it."


    • #32
      Originally posted by L_A_G View Post
      I quite frankly don't care that much about the transistor density seeing how we're talking about embedded systems where power consumption is of paramount importance. The main factor in how much power a chip draws comes from the transistors switching between their "on" and "off" states. Lowered power consumption when you move to a higher precision process mainly comes from the fact that when you move to a new process, you reduce the current difference in between the "on" and "off" states of transistors meaning that there's less energy being wasted every time a transistor goes from one state to the other.
      Yep, that's one of the ways finer processes let you reduce power consumption (strictly speaking it's lower capacitance and hence less area under the current X time curve) - ability to operate at lower voltages is the other big one - although leakage also tends to go up with finer processes so it's not a total win.

      Originally posted by L_A_G View Post
      While cramming more and more transistors onto the same chip might do a lot of good for performance, it's doesn't help with efficiency which is why we've been seeing TDP's of AMD's higher end chips reach as high as 220W. While I do believe you that these extra transistors have helped improve performance, I don't think it's done anywhere near as much good for power efficiency.
      Have to disagree here -- the high power chips you are talking about are the ones which stayed on the same process but were able to clock higher through a combination of process tweaks and higher operating voltage. Higher voltage and higher clocks are a double hit on power (triple if you count the V-squared term ).

      Using extra transistors to implement "wider logic running at a lower clock with the same or better performance" is one very important way of reducing power consumption. Reducing the clock helps somewhat, but being able to reduce the voltage (which running at a lower clock lets you do) helps even more.

      Agree that if you only use the wider logic for more performance at same clocks that isn't going to help, but that's not what we are doing.
      Last edited by bridgman; 14 December 2015, 07:55 PM.
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