curious question about the 5ghz limit or wall

[SirTexas]

im curious about something i have an 8700k in my windows computer and id like to know about the 5ghz overclock thing whats the difference between a 8700k running at 5ghz and a 9900k running at 5ghz it sounds like theres no difference why cant CPUs be overclocked even higher than 5ghz hell why cant 5ghz be the base clock speed and like 10ghz be overlocked speeds of newer CPUs is there something im not understanding did we hit some kind of limit a single CPU can do?

[Fasauceome]

1 minute ago, SirTexas said:

why cant CPUs be overclocked even higher than 5ghz

Says who

[minibois]

Intel has essentially been on the same architecture for the last 5 years+, so it's not much of a wonder why they must hit a certain wall some time.

I mean, we have seen even an FX 9590 hit 5.1Ghz and some chips even more on LN2, so it's not like it's the theoretical limit, but more like the practical limit.

 

At some point you will be hitting thermal limits, or just limits on how far the silicon goes.

[SirTexas]

Just now, Fasauceome said:

Says who

serious answer please

[Fasauceome]

1 minute ago, SirTexas said:

serious answer please

Serious answer is yes, we have hit a clock speed limit with current CPU technology that's very hard to break.

 

But I mean what I said, CPUs can be overclocked over 5GHz. world record holders for CPU clock speeds get pretty close to 10GHz

[SirTexas]

7 minutes ago, Fasauceome said:

Serious answer is yes, we have hit a clock speed limit with current CPU technology that's very hard to break.

 

But I mean what I said, CPUs can be overclocked over 5GHz. world record holders for CPU clock speeds get pretty close to 10GHz

so is there a difference between a 8700k running at 5ghz vs a 9900k running at 5ghz

[Zando_]

2 minutes ago, SirTexas said:

so is there a difference between a 8700k running at 5ghz vs a 9900k running at 5ghz

Maybe, there may be a very slight IPC increase between the two. With the 9900KS, it's actually got a very slight IPC decrease from the 9900K. KS also clocks higher on average though (5.3 on air should be a lot more common than on the 9900K and 8700K, though good chips from those models will still clock similarly, and good 8086Ks did as well) so it can overcome that slight nerf. 

[Mira Yurizaki]

24 minutes ago, SirTexas said:

im curious about something i have an 8700k in my windows computer and id like to know about the 5ghz overclock thing whats the difference between a 8700k running at 5ghz and a 9900k running at 5ghz it sounds like theres no difference why cant CPUs be overclocked even higher than 5ghz hell why cant 5ghz be the base clock speed and like 10ghz be overlocked speeds of newer CPUs is there something im not understanding did we hit some kind of limit a single CPU can do?

There's two major reasons why clock speeds tend to hit a wall:

• Power budget. Clock speed is directly related to how much power a processor will dissipate, which in turn means how much heat it generates. Sure we can make processors run to 7-8GHz, but they're outputting so much heat that it requires basically running freezer unit directly on the processor to keep it from frying.
• Timing issues. Instructions are processed on the CPU in stages. Some stages may become a bottleneck, meaning it limits the actual performance in the end. For example if we had this setup:
  
  And stage 3 was the bottleneck, then increasing the clock speed means that while the rest of the stages complete their work in a shorter amount of time, stage 3 will just hold up the line rendering all of that time savings moot:
  

There's probably other reasons other things, but those are the two primary ones.

[Guest]

1 hour ago, SirTexas said:

im curious about something i have an 8700k in my windows computer and id like to know about the 5ghz overclock thing whats the difference between a 8700k running at 5ghz and a 9900k running at 5ghz it sounds like theres no difference why cant CPUs be overclocked even higher than 5ghz hell why cant 5ghz be the base clock speed and like 10ghz be overlocked speeds of newer CPUs is there something im not understanding did we hit some kind of limit a single CPU can do?

You experience a thermal wall.

 

Look into de-lidding and using Liquid Metal under the IHS plate. You'll drop around 15-20c in temps just from that alone.

 

I run 5.4ghz with HT off, 5.3ghz with HT on. 

(turning off HT helps reduce thermals and power consumption.)

 

The reason for lower base clocks is the pipeline length. That's why AMDs FX series processors (long pipelines) where hitting beyond 8ghz on LN2, I've had mine mid 7ghz. Transisor density, TLB errata and various other things prevent chips from being really high in frequency. 

 

But technically, the manufacturers build the cpu as best as possible for efficiency and per core IPC. 

IPC does not come directly from cpu frequency either. Other variables like memory speed and latency increase this performance.

 

So it is possible to have a processor that is only 4ghz be faster than a cpu that is 4.7ghz. Intel (of the same era as->) vs AMD FX is a very good example of this.

[TopHatProductions115]

There is no wall. Only temporary limitations... 

[SirTexas]

35 minutes ago, TopHatProductions115 said:

There is no wall. Only temporary limitations... 

well its a good thing its not my job to create the next generation of CPUs that has a base clock speed of 5ghz and can overclock to 10ghz

[Mister Woof]

8 hours ago, SirTexas said:

so is there a difference between a 8700k running at 5ghz vs a 9900k running at 5ghz

2 cores and $150