The Ryzen 7 5800X3D is AMD’s first consumer release for its 3D V-cache technology, which adds another 64MB of L3 cache to its chips by physically mounting the cache on top of an existing CPU. The original CPU has been scaled back slightly to make room for this cache, to ensure the overall package looks like any other Zen 3 CPU. This means it will work with existing coolers on existing motherboards. So far so good.
However, there is a downside to adding this cache, and that is that AMD had to disable overclocking on the 5800X3D – it’s actually something Robert Hallock confirmed a month ago. This is because frequency and voltages are so inextricably linked to how this cache works that any tweaks to the CPU settings can mess up the timings and ruin everything.
Not only can you not overclock the chip, but underclocking is also out, as is undervolting, and getting more performance out of it using PBO, AMD’s Precision Boost Overdrive. PBO is an automatic overclocking scheme that increases the chip’s power budget to increase performance. It’s been the preferred way to get a little more performance out of AMD’s chips for the last few generations, and the fact that it’s not available here is somewhat surprising.
For many gamers, this isn’t the end of the world, as many won’t come close to any form of overclocking, not even fire and forgetting the ease of PBO. This means there’s little point in overdoing cooling your system, as there’s no way you can benefit from such efforts.
Before tinkerers collectively turn their backs on the new chip, there’s some good news here, which is that the Infinity Fabric and memory bus can still be overclocked. So if you don’t want to get the most out of the Ryzen 7 5800X3D, there’s still something to play with. And playing around with the 5800X3D is certainly its raison d’être, as that extra L3 cache can work wonders for some but not all games.
Where there’s a will, there’s a way pic.twitter.com/q7yYE6whpmApril 13, 2022
Some people have had luck using BCLK overclocking to get a little extra performance out of their samples, however, which suggests that higher speeds are possible. For our part, in the Gigabyte X570 Aorus Master, we had no luck pushing our chip even further through the judicious movement of the BCLK stick.
But let’s keep connecting and see if this goes anywhere.