Thursday, March 17th 2022
AMD's Robert Hallock Confirms Lack of Manual CPU Overclocking for Ryzen 7 5800X3D
In a livestream talking about AMD's mobile CPUs with HotHardware, Robert Hallock shone some light on the rumours about the Ryzen 7 5800X3D lacking manual overclocking. As per earlier rumours, something TechPowerUp! confirmed with our own sources, AMD's Ryzen 7 5800X3D lacks support for manual CPU overclocking and AMD asked its motherboard partners to remove these features in the UEFI. According to the livestream, these CPUs are said to be hard locked, so there's no workaround when it comes to adjusting the CPU multiplier or Voltage, but at least AMD has a good reason for it.
It turns out that the 3D V-Cache is Voltage limited to a maximum of 1.3 to 1.35 Volts, which means that the regular boost Voltage of individual Ryzen CPU cores, which can hit 1.45 to 1.5 Volts, would be too high for the 3D V-Cache to handle. As such, AMD implemented the restrictions for this CPU. However, the Infinity Fabric and memory bus can still be manually overclocked. The lower Voltage boost also helps explain why the Ryzen 7 5800X3D has lower boost clocks, as it's possible that the higher Voltages are needed to hit the higher frequencies.
That said, Robert Hallock made a point of mentioning that overclocking is a priority for AMD and the Ryzen 7 5800X3D is a one off when it comes to these limitations. The reason behind this is that AMD is limited by the manufacturing technology available to the company today, but it wanted to release the technology to consumers now, rather than wait until the next generation of CPUs. In other words, this is not a change in AMD's business model, as future CPUs from AMD will include overclocking.
Hallock also explained why AMD didn't go with more cores for its first 3D V-Cache CPU and it has to do with the fact that most workloads outside of gaming don't reap much of a benefit. This is large due to how different applications use cache memory and when it comes to games, a lot of the data is being reused, which is a perfect scenario for a large cache, whereas something like video editing software, can't take advantage of a large cache in the same way. This means that AMD's secret to boosting the performance in games is that more game data ends up sitting closer to the CPU, which results in a 12 ns latency for the CPU to retrieve that data from the L3 cache, compared to 60-80 ns when the data has to be fetched from RAM. Add to this the higher bandwidth of the cache and it makes sense how the extra cache helps boost the performance in games.
For more details, please see video below. The interesting part starts around the 45:30 mark.
It turns out that the 3D V-Cache is Voltage limited to a maximum of 1.3 to 1.35 Volts, which means that the regular boost Voltage of individual Ryzen CPU cores, which can hit 1.45 to 1.5 Volts, would be too high for the 3D V-Cache to handle. As such, AMD implemented the restrictions for this CPU. However, the Infinity Fabric and memory bus can still be manually overclocked. The lower Voltage boost also helps explain why the Ryzen 7 5800X3D has lower boost clocks, as it's possible that the higher Voltages are needed to hit the higher frequencies.
Hallock also explained why AMD didn't go with more cores for its first 3D V-Cache CPU and it has to do with the fact that most workloads outside of gaming don't reap much of a benefit. This is large due to how different applications use cache memory and when it comes to games, a lot of the data is being reused, which is a perfect scenario for a large cache, whereas something like video editing software, can't take advantage of a large cache in the same way. This means that AMD's secret to boosting the performance in games is that more game data ends up sitting closer to the CPU, which results in a 12 ns latency for the CPU to retrieve that data from the L3 cache, compared to 60-80 ns when the data has to be fetched from RAM. Add to this the higher bandwidth of the cache and it makes sense how the extra cache helps boost the performance in games.
For more details, please see video below. The interesting part starts around the 45:30 mark.
222 Comments on AMD's Robert Hallock Confirms Lack of Manual CPU Overclocking for Ryzen 7 5800X3D
We have also been told that there were thermal issues earlier on, and that they had to downclock it to make it run at a more suitable temperature. AMD maybe got a little bit carried away by the new packaging tech, and thought they could glue on some cache, and all would be well, and it would be a cheap solution.
The benchmarks will be interesting. But I hope that cannibalizing the sales of the already existing 5800x, as well as the 5900x and possibly 5950x were worth AMD's experiment.
It's the age old I-want-something-for-nothing argument, just because you're only willing to pay extra for more cores and nothing else.
If it beats the 5900X in gaming, and I'm not saying that it does (I know the demo used 12 core models), then why not charge a premium for it? Hint: You're not paying for more cores, you pay for extra cache.
It's for gaming, you can't overclock manually.. if you don't like it then don't buy it.Just no. That's not a proof, that's a guess at best.
If the 3D cache was anywhere close to unreliable like you suggest then AMD wouldn't launch Milan-X this month.
This CPU won't cannibalize anything. Why? Well read this thread and you'll get a few hints. Nobody thinks this is a bargain so far at $450.
Besides, this CPU is supposed to have limited availability, although we'll see about that..
None of it was an emergency, it was just another AGESA update from AMD and a beta version at that.
This seems quite innovative and will be cool to see how it plays out as consumers get hold of the chips.
We are actually lucky the cpu companies are open about their products like this, they could just say "15 % faster but its our secret sauce", as now of course Intel will probably make their own stacked cache on a future gen.
On the flip side, lower maximum Vcore and boost clocks should mean lower power consumption and temperature. And perhaps we'll see stable 2000+ MHz on the IF as well.
I'll probably still end up getting one. My current workloads would see some improvement from Zen 3 IPC lift, as well as having access to 8 physical cores.
The amount of FUD in this thread is astonishing.
"Why should I pay for higher performance when it runs at lower clocks? Them clocks = my epeen. Lower clocks should mean lower price. I measure performance in Hz."
"This thing will break, and that's why AMD have decided to also destroy their entire server market this month."
"The extra cache is in fact a couple of 5G chips. I said it, which means it is the proof of what I said."
I guess we'll see. I certainly hope it's just a matter of thermals and AMD playing it safe for tbe first time in forever. Every generation we get increasing granularity and precision in terms of voltage domains and clock dividers - cache might be the next one.
Nvidia locked down mobile GPU OCing over voltage concerns too, and the community ripped them a new one.
But when AMD does it its OK.
It's not like you don't have options. Drop the bitterness. :)
Did the video contain any test against 12900k ?
If not who cares :laugh: