5 ms·

Interesting that TDP increased from 65W on Ryzen 5 5600X to 105W on Ryzen 5 7600X, even though 7600X uses a newer process.

KSS42 4y ago
Partially due to PCIe5 and DDR5.
baobob 4y ago
The entire chip is probably just one giant fully utilized vector unit by now
neogodless 4y ago
Connect all the data points: * Zen 4 is more efficient (up to 74% more efficient at 65W) * Zen 4 will be used for desktop, server and mobile chips * Ryzen 7000 is clocked a good bit higher than Ryzen 5000 * On the desktop, higher maximum clock speeds for single and multi-core workloads are desired * The higher TDP is to allow for higher clock speeds for single and multi-core workloads on the desktop
- pier25 4y ago
  > Zen 4 is more efficient (up to 74% more efficient at 65W) So the TDP doesn't scale linearly?
  - neogodless 4y ago
    TDP isn't something that scales. > TDP stands for Thermal Design Power, in watts, and refers to the power consumption under the maximum theoretical load. [0] It's basically a ceiling. [0] https://www.intel.com/content/www/us/en/support/articles/000055611/processors.html https://www.intel.com/content/www/us/en/support/articles/000...
    - pier25 4y ago
      Yeah very poorly phrased on my part, sorry. Since you mentioned "up to 74% more efficient at 65W" what I meant is if the perf per watt (and hence the temp) doesn't scale linearly with the amount of work. The 7700X has about double the TDP of the 3700X but about a 50% increase in perf.
      - neogodless 4y ago
        That is correct. I think it's always been the case that as clock speeds increase, power draw and heat generation accelerate (diminishing returns). When you're comparing 7700X to 3700X, are you talking about performance at the same TDP limits, the same clock speed, or maximum performance?
        pier25 4y ago
        I'm comparing max perf and TDP.
  - qball 4y ago
    Not when it comes to clock speed. Note that the total power a CPU draws is proportional to its capacitance (fixed) * its frequency * the square of its voltage + some other stuff that's generally the same across CPUs of the same generation. But that doesn't quite tell the whole story, either; as you increase the frequency you also have to feed more voltage to the CPU to keep it stable for signal-processing reasons (a higher voltage means more difference between 0 and 1, and when you're right on the edge of it not working that will make the difference between a successful compute and a crash). As such, when you're trying to make a CPU and want to chase clocks, you get bit twice: first by the increased frequency due to physics, and twice by the (square of the) increased voltage requirements for stability. So running at 6 GHz and requiring 1.2V to get there is significantly more expensive power-wise than running that same processor at 4 GHz and only needing 0.8V. The only real way to fix that is microarchitecture, of course; the trick with Intel in particular is that they've been milking the same architecture they came up with in 2007 and aside from adding some Atom cores to its latest models have done basically nothing but shrink the die so it's natural that they're falling behind now.
sliken 4y ago
AMD could cap the 7600X at 65 watts, would that make you happier? Perf/watt has substantially improved, as have capability (like double the memory speed, double the memory channels, and double the PCIe bandwidth). Sure if power and cooling are available it clocks up higher, but you don't have to. Most BIOS will let you control the clock speed if you want.
- Tuna-Fish 4y ago
  > AMD could cap the 7600X at 65 watts, would that make you happier? Even more, you can cap the 7600X at 65W. All AMD cpus have configurable TDP, the advertised number is the default. Going above is overclocking, but dropping it is within spec. If you do it, your cpu will just use less power under load and be a bit slower.
  - sliken 4y ago
    Indeed, the nice thing is power use grows quickly with clock, so even something like 5GHz vs 5.5GHz can allow a chip to run a fair bit cooler, and since there's various bottlenecks like memory latency that the performance difference will be less than 10%.

KSS42 4y ago

Partially due to PCIe5 and DDR5.

baobob 4y ago

The entire chip is probably just one giant fully utilized vector unit by now

neogodless 4y ago

Connect all the data points: * Zen 4 is more efficient (up to 74% more efficient at 65W) * Zen 4 will be used for desktop, server and mobile chips * Ryzen 7000 is clocked a good bit higher than Ryzen 5000 * On the desktop, higher maximum clock speeds for single and multi-core workloads are desired * The higher TDP is to allow for higher clock speeds for single and multi-core workloads on the desktop

pier25 4y ago
> Zen 4 is more efficient (up to 74% more efficient at 65W) So the TDP doesn't scale linearly?
- neogodless 4y ago
  TDP isn't something that scales. > TDP stands for Thermal Design Power, in watts, and refers to the power consumption under the maximum theoretical load. [0] It's basically a ceiling. [0] https://www.intel.com/content/www/us/en/support/articles/000055611/processors.html https://www.intel.com/content/www/us/en/support/articles/000...
  - pier25 4y ago
    Yeah very poorly phrased on my part, sorry. Since you mentioned "up to 74% more efficient at 65W" what I meant is if the perf per watt (and hence the temp) doesn't scale linearly with the amount of work. The 7700X has about double the TDP of the 3700X but about a 50% increase in perf.
    - neogodless 4y ago
      That is correct. I think it's always been the case that as clock speeds increase, power draw and heat generation accelerate (diminishing returns). When you're comparing 7700X to 3700X, are you talking about performance at the same TDP limits, the same clock speed, or maximum performance?
      - pier25 4y ago
        I'm comparing max perf and TDP.
- qball 4y ago
  Not when it comes to clock speed. Note that the total power a CPU draws is proportional to its capacitance (fixed) * its frequency * the square of its voltage + some other stuff that's generally the same across CPUs of the same generation. But that doesn't quite tell the whole story, either; as you increase the frequency you also have to feed more voltage to the CPU to keep it stable for signal-processing reasons (a higher voltage means more difference between 0 and 1, and when you're right on the edge of it not working that will make the difference between a successful compute and a crash). As such, when you're trying to make a CPU and want to chase clocks, you get bit twice: first by the increased frequency due to physics, and twice by the (square of the) increased voltage requirements for stability. So running at 6 GHz and requiring 1.2V to get there is significantly more expensive power-wise than running that same processor at 4 GHz and only needing 0.8V. The only real way to fix that is microarchitecture, of course; the trick with Intel in particular is that they've been milking the same architecture they came up with in 2007 and aside from adding some Atom cores to its latest models have done basically nothing but shrink the die so it's natural that they're falling behind now.

sliken 4y ago

AMD could cap the 7600X at 65 watts, would that make you happier? Perf/watt has substantially improved, as have capability (like double the memory speed, double the memory channels, and double the PCIe bandwidth). Sure if power and cooling are available it clocks up higher, but you don't have to. Most BIOS will let you control the clock speed if you want.

Tuna-Fish 4y ago
> AMD could cap the 7600X at 65 watts, would that make you happier? Even more, you can cap the 7600X at 65W. All AMD cpus have configurable TDP, the advertised number is the default. Going above is overclocking, but dropping it is within spec. If you do it, your cpu will just use less power under load and be a bit slower.
- sliken 4y ago
  Indeed, the nice thing is power use grows quickly with clock, so even something like 5GHz vs 5.5GHz can allow a chip to run a fair bit cooler, and since there's various bottlenecks like memory latency that the performance difference will be less than 10%.