AMD's enthusiast-grade Ryzen 7 5800X3D processor with a massive 96MB L3 cache supports everything that the company's latest CPU series has to offer in an attempt to be the best CPU for gaming, but according to a post on Bilibili that also features the first known picture of the chip, the chip doesn't support overclocking. A recent video interview with AMD representatives also implies that this could be the case (below).
As you can see above, the Bilibili poster claims the chip isn't overclockable, which makes plenty of sense. When AMD announced its Ryzen 7 5800X3D processor several months ago, it emphasized its gargantuan 96MB L3 cache and increased single-thread performance thanks to fast memory accesses, an important factor for games. However, AMD didn't emphasize overclocking capabilities or clock rates compared to the regular Ryzen 7 5800X model.
Apparently, to add cache, AMD had to sacrifice clock speeds and may have also cut overclocking support. Additionally, AMD's website doesn't list the chip as overclockable, while it does list other models, like the standard 5800X, as overclockable.
TechPowerUp also claims that AMD is asking its motherboard partners to disable overclocking support for its Ryzen 7 5800X3D chip, as despite the X letter in its model number, it is not exactly overclocking friendly.
There are technical reasons why AMD's Ryzen 7 5800X3D had to lower clocks and disable overclocking. First, AMD places its 3D V-Cache on top of Zen 3's 'native' L3 cache and then connects them using through silicon vias (TSVs). This creates a non-uniform surface of the die, complicating positioning the integrated heat spreader (IHS) on top of the chip. To make it even, AMD places structural silicon spacers on top of Zen 3's processing cores, which limits their ability to dissipate heat. Yes, silicon does serve as a good thermal conductor, but it still traps a non-zero amount of heat between the die, structural silicon, and IHS.
Because a 64MB 3D V-Cache tile also adds to the power consumption, AMD had to lower the base clocks by 400 MHz to maintain a 105W default TDP. For the same reason, overclocking capabilities are likely also affected, so disabling overclocking support on X3D CPUs makes sense.
|Header Cell - Column 0||Cores | Threads||L3 Cache||P-Core Base/Boost||TDP / PBP / MTP|
|Ryzen 7 5800X3D||8P | 16 threads||96MB||3.4 / 4.5 GHz||105W|
|Ryzen 7 5800X||8P | 16 threads||32MB||3.8 / 4.7 GHz||105W|
|Ryzen 9 5900X||12P | 24 threads||32MB||3.7 / 4.8 GHz||105W|
Finally, a recent video interview with AMD's Robert Hallock and Frank Azor could also be telling. As you can see at 7:55 in the above video, Azor asked Hallock about Ryzen 7 5800X3D overclocking back in January, but Hallock didn't confirm the feature. That implies that perhaps X3D models were simply not designed to be overclockable.
Also, in reality, there's no such thing as "not overclockable" IMO and it will depend on what is exposed to the motherboard in terms of voltage control, multipliers and such.
It's definitely not a good message to put out there, but I think the devil will be in the details.
Heat was always a concern of mine when I heard they were going to stack chips. Eventually backplate heatsinks are coming with an entirely new socket design to support it where CPU pads are outside the core area to allow an open area in the middle on both sides to cool.
Forcing the CPU to run over its stock base speed, which I argue when placed in a vacuum, this is what "overclocking" should mean since this is how it's always been done.
Allowing the CPU to run over its advertised maximum turbo boost speed.In any case, if a "locked" AMD CPU simply means you can't change the multiplier past, in this case, 45, then you can still do base speed overclocking. Setting a value on the multiplier forces the CPU to run at that speed all the time. If it's say disabling PBO features or whatnot, a little more painful, but not exactly a huge loss considering you can barely push the maximum turbo speed on Ryzens anyway. Plus said maximum turbo speed is only good for the preferred cores.
What i expect is that this is engineering sample and there quite often are some limitations with engineering samples...
PBO effectively makes manual overclocking mostly pointless, and hopefully theyll be a good upgrade option for anyone thats on a B450 board or newer. If youre happy with your current setup why change out your whole platform when you can just replace your cpu and get a nice performance lift?
And of course, AMD has stated that the 5800X3D will be the "World's Fastest Gaming CPU", so I don't think the Intel chips will "smash it", as it will likely hold the lead in at least some workloads. Whether that justifies its price is yet to be seen, but there are people who will pay a big premium for imperceptable performance gains, like those putting 12900Ks into gaming systems, rather than processors costing around half as much with very similar gaming performance.
It doesn't sound like a hardware lockout if AMD's asking board partners to not allow overclocking. I expect leaked...or hacked... BIOS's to show up for some boards anyway and attempts made.