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Dumb question: What is the difference (implication-wise) between being overclocked at 5GHz and not-being-overclocked but still at 5GHz? My CPU (just like any ot

Dumb question: What is the difference (implication-wise) between being overclocked at 5GHz and not-being-overclocked but still at 5GHz? My CPU (just like any other modern CPU) limits its clock speed to regulate its own temperature despite the fact that it's not even unlocked to let me overclock it, so it's not the difference is throttling. So what's the difference?

captainbland 8y ago
I guess they're just trying to say it won't be released as a 5GHz stock clockspeed - it probably goes over their TDP limits. Edit: And here I learn to read the article first: It's almost definitely that they couldn't achieve it with stock air cooling based on the setup described in the article.
- zaarn 8y ago
  I think going over the TDP limits is putting it lightly considering it was outputting 2 watts per square millimeter. For comparison, a Ryzen 1800X does 0.49 watts per square millimeter and has a lot less square millimeters (probably less than half)
  - tutanchamun 8y ago
    The Xeon 28 core part seems to be 698mm² [0] while the AMD Ryzen 1800X is 213mm² [0] https://www.anandtech.com/show/11839/intel-core-i9-7980xe-and-core-i9-7960x-review/3 https://www.anandtech.com/show/11839/intel-core-i9-7980xe-an...
cjslep 8y ago
"Not being overclocked" at 5GHz means the system is designed to run at that speed off the shelf without becoming molten slag and without aftermarket industrial grade cooling systems.
- mehrdadn 8y ago
  So it's not the fact that it was overclocked that matters, but the fact that it required aftermarket cooling, right? Like my current CPU cannot get within 100MHz of its supposed max TurboBoost frequency due to (I presume) cooling limits, despite the fact that I haven't overclocked it, so for me to even get the frequency it is marketed as I would need aftermarket cooling... which seems like the same problem despite the lack of overclocking, right?
  - syrgian 8y ago
    Many times the announced max frequency is for single-core usage. If you're using all the cores they all have to slow down collectively so the whole CPU doesn't overheat.
    - mehrdadn 8y ago
      Everything I'm talking about is single-threaded use only.
  - montalbano 8y ago
    Overclocking sometimes invalides warantee. Overclocking almost always shortens life expectancy of the CPU.
    - mehrdadn 8y ago
      Ahh, so the difference is the voiding of the warranty? If so then this seems to explain why it would be more than a naming issue.
      - NullPrefix 8y ago
        It's in the category of "It may or may not work, YMMV, don't call us if you mess up".
      - floofyreal 8y ago
        He didn't mean it like that (or at least I think he didn't). Imagine it like person walking/running - When you are expect to walk at some pace (5GHz) you can do it proficiently for long time, considering you get your regular inputs and outputs taken care of (basic cooling, regular power drain), when you overclock - run, you need much more care to be able to run for a long time (stronger cooling, more power headroom, overclocking motherboard). What Intel in this demo did is strapped you behind the car and drove a 100 meters dash proclaiming - look he survived, he 'ran' that 100 meters run like a champ, it's possible to run this fast.
buserror 8y ago
It changes the maximum speed attainable by that CPU, and allows to maintain it for longer. You can change pretty easily the maximum clock multiplier the CPU is allowed to use (on K CPUs at least) -- but doing so without proper cooling and proper power supply will just crash. SOME 'good' bin CPU can be overclocked a fair amount without extra power/cooling, but it's always touch an go. My workstation still has a 4600K i7 that has been running at 5ghz for probably 5 years, without even pushing the voltage. It's in fact a lot quicker (single thread) than a more modern system I built since. That was a "good bin"! the 4500 and 4600 were known for their overclock potential.
dreta 8y ago
The CPU requiring a massive cooling system to run at the advertised frequency is an important information to share with the consumer.
pdpi 8y ago
When you say “here’s a 5GHz CPU” you expect it to fit with the current product lineup and to have thermal and power requirements within certain parameters that would allow you to run the thing at 5GHz without much effort. “We overclocked this CPU to 5GHz” means all bets are off. You often have some headroom to overclock on stock voltage/cooling but always need to go above and beyond for more extreme overclocking. This particular setup apparently was using a very fancy 1700ish W chiller, and a 1300W PSU for the chassis itself. Also, this is a Xeon part, so one you’d expect to see in servers or workstations. You don’t want that sort of thermals anywhere close to a data centre rack, and the sort of business with the budget to give you this sort of CPU wouldn’t want to have their IT department assembling custom coolers like this. All of this assumes, of course, you can run the chip stably. That's more or less a given at stock speeds, operating within the vendor's operational specs. Once you start overclocking, all bets are off. Extreme overclocking (the sort that uses liquid nitrogen or this sort of chiller) never lasts long. Again, something an enthusiast overclocking for a few FPS on a gaming rig might be willing to live with, but a problem that's seriously disruptive in the sort of environment a Xeon is likely to be deployed. (EDIT: Fixed chiller power and added stability concerns)
- NullPrefix 8y ago
  >fancy 1kW chiller It was 1770W, not 1000W
  - dingo_bat 8y ago
    The mobo had a 16 phase power delivery system designed to pump 1kw into the CPU itself. Kind of mindblowing actually.
  - parimm 8y ago
    The chiller unit consumes 1kW of power and produces 1.7kW of cooling
    - yyx 8y ago
      Can you get 1kW of power from 1.7kW of cooling to power chiller unit?
tutanchamun 8y ago
The guarantee to get a CPU which can run stable 5ghz on all cores within the TDP limit and only requiring a cooling solution which can handle the TDP. If you need to overclock you don't get this and have to buy more expensive cooling and probably need to de-lit (remove the heatspreader) of your above 2000 dollar CPU (which can permanently damage it) to improve the thermals because Intel - unlike AMD - didn't solder their heatspreader. Even then, you're not guaranteed to get a chip which can run 5 ghz on all cores 24/7. The best 18 core HEDT from Intel I have seen to date was running 4.5ghz on all cores 24/7 with delidding and a custom loop. The 28 core Xeon which this probably is based upon runs 2.5 ghz stock and can boost to 3.8 ghz on a single core (3 or 3.2 ghz on all cores I believe).
gaius 8y ago
What is the difference (implication-wise) between being overclocked at 5GHz and not-being-overclocked but still at 5GHz It’s like extrapolating from an athletes 100m sprint time to their Marathon time. In other words, taking peak performance and presenting it as something that can be sustained for long periods.
- geezerjay 8y ago
  That's a great analogy.
- floatboth 8y ago
  This analogy is not about overclocking in general: if you OC for daily use you run stress tests and make sure it's stable. But yeah, this is absolutely the case with the Intel demo. Their demo proved that the chip can run Cinebench at 5GHz. Cinebench is not the heaviest load and it finishes very, very quickly. If they showed Prime95 AVX with small FFTs running for a couple hours, that would count as stable :D
Symmetry 8y ago
For extreme overclocking like this I'd expect the voltages and temperatures involved to result in a lot of electromigration inside the chip, wearing it out and causing it to stop functioning eventually.
Sohcahtoa82 8y ago
If you buy a car that has an engine that produces 400 horsepower, you can reasonably expect it to run reliably. Every part will have been designed to handle the power output of that engine. On the flip side, if you buy a car that has an engine that produces only 200 horsepower, but then add a large turbocharger that boosts the output to 400 horsepower, you're likely to run into problems. The cooling system might not keep up. The engine block internals might not be able to handle the extra pressure. The transmission or differential might not be able to survive the excess torque. Your clutch might slip. Similar idea to a CPU. Transistors can only switch so fast. If you buy a CPU that Intel labels as a 5 Ghz CPU, Intel is guaranteeing those transistors can switch fast enough to maintain that clock speed. If you buy one that's only 4 Ghz and try to overclock it, there might be some transistors in that chip that can't switch that fast. Increasing voltage can help, but now you're creating more heat.

captainbland 8y ago

I guess they're just trying to say it won't be released as a 5GHz stock clockspeed - it probably goes over their TDP limits. Edit: And here I learn to read the article first: It's almost definitely that they couldn't achieve it with stock air cooling based on the setup described in the article.

zaarn 8y ago
I think going over the TDP limits is putting it lightly considering it was outputting 2 watts per square millimeter. For comparison, a Ryzen 1800X does 0.49 watts per square millimeter and has a lot less square millimeters (probably less than half)
- tutanchamun 8y ago
  The Xeon 28 core part seems to be 698mm² [0] while the AMD Ryzen 1800X is 213mm² [0] https://www.anandtech.com/show/11839/intel-core-i9-7980xe-and-core-i9-7960x-review/3 https://www.anandtech.com/show/11839/intel-core-i9-7980xe-an...

cjslep 8y ago

"Not being overclocked" at 5GHz means the system is designed to run at that speed off the shelf without becoming molten slag and without aftermarket industrial grade cooling systems.

mehrdadn 8y ago
So it's not the fact that it was overclocked that matters, but the fact that it required aftermarket cooling, right? Like my current CPU cannot get within 100MHz of its supposed max TurboBoost frequency due to (I presume) cooling limits, despite the fact that I haven't overclocked it, so for me to even get the frequency it is marketed as I would need aftermarket cooling... which seems like the same problem despite the lack of overclocking, right?
- syrgian 8y ago
  Many times the announced max frequency is for single-core usage. If you're using all the cores they all have to slow down collectively so the whole CPU doesn't overheat.
  - mehrdadn 8y ago
    Everything I'm talking about is single-threaded use only.
- montalbano 8y ago
  Overclocking sometimes invalides warantee. Overclocking almost always shortens life expectancy of the CPU.
  - mehrdadn 8y ago
    Ahh, so the difference is the voiding of the warranty? If so then this seems to explain why it would be more than a naming issue.
    - NullPrefix 8y ago
      It's in the category of "It may or may not work, YMMV, don't call us if you mess up".
    - floofyreal 8y ago
      He didn't mean it like that (or at least I think he didn't). Imagine it like person walking/running - When you are expect to walk at some pace (5GHz) you can do it proficiently for long time, considering you get your regular inputs and outputs taken care of (basic cooling, regular power drain), when you overclock - run, you need much more care to be able to run for a long time (stronger cooling, more power headroom, overclocking motherboard). What Intel in this demo did is strapped you behind the car and drove a 100 meters dash proclaiming - look he survived, he 'ran' that 100 meters run like a champ, it's possible to run this fast.

buserror 8y ago

It changes the maximum speed attainable by that CPU, and allows to maintain it for longer. You can change pretty easily the maximum clock multiplier the CPU is allowed to use (on K CPUs at least) -- but doing so without proper cooling and proper power supply will just crash. SOME 'good' bin CPU can be overclocked a fair amount without extra power/cooling, but it's always touch an go. My workstation still has a 4600K i7 that has been running at 5ghz for probably 5 years, without even pushing the voltage. It's in fact a lot quicker (single thread) than a more modern system I built since. That was a "good bin"! the 4500 and 4600 were known for their overclock potential.

dreta 8y ago

The CPU requiring a massive cooling system to run at the advertised frequency is an important information to share with the consumer.

pdpi 8y ago

When you say “here’s a 5GHz CPU” you expect it to fit with the current product lineup and to have thermal and power requirements within certain parameters that would allow you to run the thing at 5GHz without much effort. “We overclocked this CPU to 5GHz” means all bets are off. You often have some headroom to overclock on stock voltage/cooling but always need to go above and beyond for more extreme overclocking. This particular setup apparently was using a very fancy 1700ish W chiller, and a 1300W PSU for the chassis itself. Also, this is a Xeon part, so one you’d expect to see in servers or workstations. You don’t want that sort of thermals anywhere close to a data centre rack, and the sort of business with the budget to give you this sort of CPU wouldn’t want to have their IT department assembling custom coolers like this. All of this assumes, of course, you can run the chip stably. That's more or less a given at stock speeds, operating within the vendor's operational specs. Once you start overclocking, all bets are off. Extreme overclocking (the sort that uses liquid nitrogen or this sort of chiller) never lasts long. Again, something an enthusiast overclocking for a few FPS on a gaming rig might be willing to live with, but a problem that's seriously disruptive in the sort of environment a Xeon is likely to be deployed. (EDIT: Fixed chiller power and added stability concerns)

NullPrefix 8y ago
>fancy 1kW chiller It was 1770W, not 1000W
- dingo_bat 8y ago
  The mobo had a 16 phase power delivery system designed to pump 1kw into the CPU itself. Kind of mindblowing actually.
- parimm 8y ago
  The chiller unit consumes 1kW of power and produces 1.7kW of cooling
  - yyx 8y ago
    Can you get 1kW of power from 1.7kW of cooling to power chiller unit?

tutanchamun 8y ago

The guarantee to get a CPU which can run stable 5ghz on all cores within the TDP limit and only requiring a cooling solution which can handle the TDP. If you need to overclock you don't get this and have to buy more expensive cooling and probably need to de-lit (remove the heatspreader) of your above 2000 dollar CPU (which can permanently damage it) to improve the thermals because Intel - unlike AMD - didn't solder their heatspreader. Even then, you're not guaranteed to get a chip which can run 5 ghz on all cores 24/7. The best 18 core HEDT from Intel I have seen to date was running 4.5ghz on all cores 24/7 with delidding and a custom loop. The 28 core Xeon which this probably is based upon runs 2.5 ghz stock and can boost to 3.8 ghz on a single core (3 or 3.2 ghz on all cores I believe).

gaius 8y ago

What is the difference (implication-wise) between being overclocked at 5GHz and not-being-overclocked but still at 5GHz It’s like extrapolating from an athletes 100m sprint time to their Marathon time. In other words, taking peak performance and presenting it as something that can be sustained for long periods.

geezerjay 8y ago
That's a great analogy.
floatboth 8y ago
This analogy is not about overclocking in general: if you OC for daily use you run stress tests and make sure it's stable. But yeah, this is absolutely the case with the Intel demo. Their demo proved that the chip can run Cinebench at 5GHz. Cinebench is not the heaviest load and it finishes very, very quickly. If they showed Prime95 AVX with small FFTs running for a couple hours, that would count as stable :D

Symmetry 8y ago

For extreme overclocking like this I'd expect the voltages and temperatures involved to result in a lot of electromigration inside the chip, wearing it out and causing it to stop functioning eventually.

Sohcahtoa82 8y ago

If you buy a car that has an engine that produces 400 horsepower, you can reasonably expect it to run reliably. Every part will have been designed to handle the power output of that engine. On the flip side, if you buy a car that has an engine that produces only 200 horsepower, but then add a large turbocharger that boosts the output to 400 horsepower, you're likely to run into problems. The cooling system might not keep up. The engine block internals might not be able to handle the extra pressure. The transmission or differential might not be able to survive the excess torque. Your clutch might slip. Similar idea to a CPU. Transistors can only switch so fast. If you buy a CPU that Intel labels as a 5 Ghz CPU, Intel is guaranteeing those transistors can switch fast enough to maintain that clock speed. If you buy one that's only 4 Ghz and try to overclock it, there might be some transistors in that chip that can't switch that fast. Increasing voltage can help, but now you're creating more heat.