Comment by aurareturn 8 days ago
https://tpucdn.com/review/amd-ryzen-7-9800x3d/images/efficie...
Raw gaming performance increase is good but its gaming efficiency seems to have taken a dip compared to 7800X3D.
So AMD chose to decrease efficiency to get more performance this generation.
Source: https://www.techpowerup.com/review/amd-ryzen-7-9800x3d/23.ht...
If I can summarize what you wrote: Same IPC gain as normal Zen5 but more power can be drawn to increase performance due to moving the cache chiplet to the bottom.
The previous 3D cache solutions were not just limited thermally, but also the cache chiplet could not tolerate the high voltages that AMD's CPU cores use at high frequencies. Even with excellent cooling, you weren't going to get a 7800X3D or 5800X3D to match frequencies with the non-3D parts. (This might have been less of a problem if AMD could put the extra cache on a different power rail, but that's hard to retrofit into an existing CPU socket.) This new cache chiplet still has a lower voltage limit than the CPU cores, but it's not as big a disparity.
9800X3D is supposed to have Eco mode with a lower TDP cap, similarly to other AMD processors. I don't see it included in the initial reviews, but it would be curious to see the followup data. If the history is anything to go by, it would significantly decrease the power consumption with only a marginal performance impact.
I have the 7950x, and if I set it to 65W eco mode, I still have basically the same geekbench score
65W: https://browser.geekbench.com/v6/cpu/6126001
105W: https://browser.geekbench.com/v6/cpu/5821065
I actually haven't tested it with 170W (which is the default for the 7950x) for whatever reason, but the average 7950x score on geekbench is basically the same as my geekbench scores with lower than normal TDP.
https://browser.geekbench.com/processors/amd-ryzen-9-7950x
I wouldn't be surprised if the same is possible with the newer CPUs.
Nice added bonus is that my PC fans barely spin (not at audible speeds)
Bad arch decision are punishing. AMD was absolutely dwarfed in the early core iX days and never really came back until Ryzen. The whole bulldozer linage was DoA to the point Opteron just never factored in.
Hopefully Intel pull something out again but they look asleep a the wheel.
For a long time, x86 chips are happy to give you a little more performance for a lot more watts at the top end of the performance chart.
Watts/fps @ max fps makes for an interesting graph, but not a very clear comparison. It would be better to compare watts used when locked at a given fps, or fps available when locked at a given wattage. Or watthours to do a video encode (with max wattage, and at various watt limits).
The efficiency is only worse because the CPU can use the power without burning itself up unlike the last generation's X3D. And efficiency is always better at lower clocks. You can get this generation's efficiency uplift by limiting its power to the levels where last generation's CPU started throttling to keep its 89C Tjmax, but that will inevitably also limit the frequency that's the main performance uplift for the CPU
For comparison on how limited last gen's X3D was wrt power, tom's hardware has it on 71W with all core AVX, while my 7600X with 2 fewer cores consumes up to 130W