Jovec
?
- 921
- 525
7000-series X3Ds had the vcache on top of the cores, so it was sitting between the cores and the IHS/CPU cooler so heat generated by the cores had to pass through the vcache first which limited cooling ability (initially, the thought was that the vcache was voltage/temp sensitive which is why the 7000 series X3Ds had strict votage and clock limits, but it was simply because the vcache was a bad thermal conductor - confirmed by AMD IIRC). 9000 series puts the vcache first, then the cores, then the IHS/CPU cooler, so the cores can be more effectively cooled and thus they allowed overclocking.
In a sense, delidding a 7800X3D or 9800X3D is less effective since any decent AIO or air cooler should be able to handle the heat load anyway, but there are a lot of factors that go into the boost clock states; PPT (overall power consumption), vcore and the p/f cuve, temps, etc. Debauer's 9800X3D review had his stock lidded CPU at 5225 MHz all core, while the delidded version hit 5600MHz all core (the CPU max) without any voltage tuning. It's a cycle - less heat means less voltage is needed for a given frequency which means less heat which means...up to the CPU's limit (either hard limited by AMD or soft limited by physics and CPU quality). Of course, just go 16C/32t or greater instead of delidding for better multi-core.
7800X3D clocks are locked (to the efficient portion of the volrage/freq curve) so there is no real gain to be had with direct die cooling, but the 16c CPUs have much more headroom if the temp, voltage, and wattage can be tamed, to the tune of 5-10% more performance with 5-10% less power consumed with no other tuning.
Also, I broke down and picked one up. I'm in a decent position for the current component crunch with extra RAM, GPU, and NVMe, so I can easily repurpose the 7800X3D being replaced. All my hoarding is finally paying off. 9850X3D is definitely a cash grab though, as I believe it is just the same binned CCD that went into the 9950X3D which can be had for ~$150 more right now. They have the same boost clocks on the vcache CCD. Buy that, disable the non-vcache CCD, and run a ~$650 "9850X3D" that has the potential to be a 16c/32t CPU when needed (for example, a home server in the future when we are running 10800X3Ds or whatever). At the very least much, if not all, of that ~$150 difference can be recovered during resale. I am still hoping/waiting for the 9950X3Dx2 so I don't have to deal with core scheduling, though that is much improved.
- 1
