Comment by Numerlor

Comment by Numerlor 8 days ago

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

aurareturn 8 days ago

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.

Reply View 1 reply

wtallis 7 days ago

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.

Reply View | 0 replies