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
To bad nobody thought to use 11900k which is a 8 core same as 5800x.
5800X always has 142W PPT no matter what unless you manually change it. On Intel it depends on MB, what bios you use etc.
I dont know, i feel like im being trolled..
But somehow a 10900k is ?
You first said they were equally efficient without stating that you need 125W limit for that, I disagreed, but now admit 5800X is more efficient even with 10900K running 125W limit so I`m satisfied :) It`s not about winning a discussion, it`s about getting the facts straight.
"not realising it is as efficient as the 5800x" that was your original claim which I disagreed on. A simple correction of saying it could be nearly as efficient if running 125W limit I would have had no reason to argue with you :)
At 1.35V, Zen3 is still likely going to boost to 4.6GHz based on the 5800X experiences. The cache will just have to make up for the missing 200MHz
Other than that, I don't disagree, the way Intel decides to configure most of its' cpus, they are pretty much bad when it comes to efficiency out of the box. But as ive said, that's something that you can easily change.You are right, should have mentioned it. Usually when Im talking about efficiency im talking about there being a power limit.
Yes this is a dealbreaker to stop me buying on launch day - i'll wait and see what people figure out before considering it.
I love my 5800x, but higher performance with some mitigation for the higher than usual temps is what I want from an upgrade - and i *like* my current low voltage all core overclock (1.2V, 4.6GHz)
It looks like PBO will still be around, there are reports of the 1.2.0.6B AGESA limiting 5800x CPU voltages - now we know why.
We should have PBO tweaking, just no manual voltage/multi control.
Edit as i go with replies:The 4770K I gave to my dad was the best clocking CPU i ever experienced.
From 3.5GHz base to 4.5Ghz daily (for 10 years!) without ever a crash, running 32GB of 2400MHz DDR3 (from the measly 1333Mhz jedec standard)
Absolutely amazing how well it's aged, and it outperforms quite a few modern 4 core CPUsI get that ~2% loss you showed, but with 35W less power used and 15C lower temps. There is a benefit to it.
By design it was never going to be a great oc cpu. All the extra cache requires that much more package voltage which equals heat. The second cache layer + oc voltage is gonna cook the cores on the ground floor.
It's locked because it should be. (disclamer..I like amd stuff).
1.33v ~ 1.37v is the absolute max. Anything above will seriously degrade your chip in months not even weeks.Incorrect. They said it themself the Cache is dependent of the CPU core voltage. They coud'nt design a seperate voltage rail among it due to compatible pin layouts. So you go with what you have, really. Since it's a EPYC gimmick, epyc's where never tested against OC's since the clocks of those CPU avg on 2 to 3.4Ghz.
Degradation is real; i woud'nt want to mess with the 5800X's Cache at all. If that degrades your toast. However i still believe BCLK oc'ing should be possible within the realms of acceptable voltages.
It makes me thankful that AMD surged back and basically the situation now is that overclocks are no longer easy... and this is a good thing for the majority (not so good for the overclocking enthusiast).
AMD themselves clarified that fixed voltages above 1.4V are seriously detrimental to the health of the silicon, and just because your CPU shows boost voltages of up to 1.55V in monitoring software doesn't mean that it's safe to set that as a manual voltage. The boost algorithm allows single-core peak voltages up to 1.55V only for a few hundred milliseconds at a time and software will only report the peak reading at much slower update intervals.
In reality, when you are running a single-threaded benchmark using a non-overclocked Ryzen with regular XFR boost, you're getting voltages of ~1.5V only as the final voltage before the algorithm swaps the load to another core, allowing the original core to both cool and discharge. Ryzen Master shows the core-juggling better than most software but even that doesn't paint the true picture, and was explained in more depth by Rob @amd in a tweet to der8auer. When boosting on a core, the voltage isn't fixed for the roughly half-second of load on that core; It starts off lower, at ~1.3V and ramps up as the charges and thermals in that area of silicon increase over the duration of that brief boost on the core. Over that single half-second cycle on one core, the average voltage to that core will likely still be under 1.4V and even if it isn't, the percentage of time that the core spends at voltages that could promote electromigration is so negligible that the effective time-to-death of the CPU vastly exceeds the warranty period, and likely the relevance of the CPU before obsolescence.
So much idiocy in one thread. I can't take anymore of that.