3 ms·

I'm mostly interested in numbers under 100W, maybe even 65W, since I plan to down-clock my (future) Zen 4 machine. AMD is killing it with efficiency there.

neogodless 4y ago
Yes - comparing the above 65W score from AMD to Intel's 145W score highlights the stark difference!
sliken 4y ago
I've seen several posts showing that the most minor of underclocks and undervolts produce substantial power savings and minimal performance differences. Apparently Intel's trying really hard on an old process to get the performance crown, forcing AMD to clock higher than they'd like to compete. It's ridiculous that they double the power for 10% performance. But the nice thing is you can half the power and take the 10% hit. Also note that the 7900/7900X are dual chiplet design that has a significant power impact. The 7700x and below have a single chiplet and saves power, and also increases single thread perf. If you look at the gaming benchmarks the 7700x is often better than the 7900x, not to mention all the Intel chips except the top of the line i9. So if you buy the 7700x and underclock just a bit you should have a very efficient desktop.
- neogodless 4y ago
  > the 7900/7900X are dual chiplet design This is a minor terminology mix-up. The term you want here is "CCX". Each CCX holds multiple chiplets. See https://www.tomshardware.com/reviews/amd-ccx-definition-cpu-core-explained,6338.html https://www.tomshardware.com/reviews/amd-ccx-definition-cpu-... for more details. EDIT: It does look like my own information on this was rusty. A "chiplet" is not an individual core, but a trimmed down die that does not have a memory controller. A "CCX" contains cores (within a chiplet) and L3 cache. https://www.hardwaretimes.com/amd-ccd-and-ccx-in-ryzen-processors-explained/ https://www.hardwaretimes.com/amd-ccd-and-ccx-in-ryzen-proce... > The basic unit of a Ryzen processor is a CCX or Core Complex, a quad-core/octa-core CPU chiplet with a shared L3 cache.
  - rektide 4y ago
    > For the Ryzen 3000-series processors, CCX refers to a four-core grouping inside of each core chiplet die (CCD). For example, an AMD CPU with 8 cores will have a CCD with two 4-core CCXs. From that link, your statement does not appear accurate. Multiple CCX's appear on a given Core Chiplet Die. There are indeed two vs one core chiplets on different Ryzen designs (plus the IOD).
sailplease 4y ago
check out https://arstechnica.com/gadgets/2022/10/intel-i9-13900k-and-i5-13600k-review-beating-amd-at-its-own-game/ https://arstechnica.com/gadgets/2022/10/intel-i9-13900k-and-... - they power limited both 7000 and raptor lake models and surprisingly, amd doesn't respect the power limits - at 65W it's burning 90W and intel is respecting the 65W limit, 7.868Whr vs 8.58Whr to complete the same task (h264 encoding in handbrake), so interestingly intel on a 2 node disadvantage is more power efficient if you set your power limits.

neogodless 4y ago

Yes - comparing the above 65W score from AMD to Intel's 145W score highlights the stark difference!

sliken 4y ago

I've seen several posts showing that the most minor of underclocks and undervolts produce substantial power savings and minimal performance differences. Apparently Intel's trying really hard on an old process to get the performance crown, forcing AMD to clock higher than they'd like to compete. It's ridiculous that they double the power for 10% performance. But the nice thing is you can half the power and take the 10% hit. Also note that the 7900/7900X are dual chiplet design that has a significant power impact. The 7700x and below have a single chiplet and saves power, and also increases single thread perf. If you look at the gaming benchmarks the 7700x is often better than the 7900x, not to mention all the Intel chips except the top of the line i9. So if you buy the 7700x and underclock just a bit you should have a very efficient desktop.

neogodless 4y ago
> the 7900/7900X are dual chiplet design This is a minor terminology mix-up. The term you want here is "CCX". Each CCX holds multiple chiplets. See https://www.tomshardware.com/reviews/amd-ccx-definition-cpu-core-explained,6338.html https://www.tomshardware.com/reviews/amd-ccx-definition-cpu-... for more details. EDIT: It does look like my own information on this was rusty. A "chiplet" is not an individual core, but a trimmed down die that does not have a memory controller. A "CCX" contains cores (within a chiplet) and L3 cache. https://www.hardwaretimes.com/amd-ccd-and-ccx-in-ryzen-processors-explained/ https://www.hardwaretimes.com/amd-ccd-and-ccx-in-ryzen-proce... > The basic unit of a Ryzen processor is a CCX or Core Complex, a quad-core/octa-core CPU chiplet with a shared L3 cache.
- rektide 4y ago
  > For the Ryzen 3000-series processors, CCX refers to a four-core grouping inside of each core chiplet die (CCD). For example, an AMD CPU with 8 cores will have a CCD with two 4-core CCXs. From that link, your statement does not appear accurate. Multiple CCX's appear on a given Core Chiplet Die. There are indeed two vs one core chiplets on different Ryzen designs (plus the IOD).

sailplease 4y ago

check out https://arstechnica.com/gadgets/2022/10/intel-i9-13900k-and-i5-13600k-review-beating-amd-at-its-own-game/ https://arstechnica.com/gadgets/2022/10/intel-i9-13900k-and-... - they power limited both 7000 and raptor lake models and surprisingly, amd doesn't respect the power limits - at 65W it's burning 90W and intel is respecting the 65W limit, 7.868Whr vs 8.58Whr to complete the same task (h264 encoding in handbrake), so interestingly intel on a 2 node disadvantage is more power efficient if you set your power limits.