CPU Cache Clock & Bottlenecks

[MedievalNerd]

Howdy there,

 

been coming here often but it's the first time I have a question, so so decided to register!

 

I'm currently running the following 5820k @ 4.5Ghz.

 

I've seen YT tech videos that seem to imply that the Cache Clock (uncore) isn't that important to overclock. So I never really bothered with it. But I was noticing that in some games like Planetside2, although the GPU or CPU cores weren't 100% busy I was getting performance drops. I then started messing with the Cache Clock and noticed some improvements. (used to see FPS drops in the 70's when in 200+ people battles, but now I seem to never dip below 90.) Also, I've noticed that the Cache Core Clock will tend to overclock at times where the CPU isn't at it's max frequency. (Which is why I'm wondering if it's not a bit more important than some people seem to imply)

I also started messing with the Memory clock of my 780Ti, which equally seems to have given some noticeable improvements.

 

So my questions are the following:

 

#1 - A) How much of a factor does the Cache Core play in terms of handling performance? From what I understand it's basically the hub for the CPU, RAM & GPU so should it be kept as highly clocked as possible to avoid any bottlenecks?

 

B) On this same subject, does anyone know of any software that can monitor the utilization of the Cache Core? I'm able to monitor everything except that, which would help to see how busy it is and whether or not it's worth messing about.

 

#2 - A) How much of an impact does GPU VRAM Clock speeds play in terms of performance? Can the GPU Core be stuck 'waiting' for the VRAM to transfer data to it? 

 

B) I'm running my GTX 780Ti at 1300Mhz, should there be a 'sweet spot' ratio to consider when playing with the VRAM clock?

 

Hopefully this isn't just a bunch of nonsensical questions, bit of a performance enthusiast but I think I'm lacking some pieces of information to make sure I'm not just overclocking in the dark.

 

Much appreciate any feedback, and hopefully this is the correct sub-forum section to discuss these points.

 

Cheers,

 

MedievalNerd

[ccokeman]

I usually run the cache ring frequency as high as my chip will allow. The problem is that as you increase it you lose both overall core clock frequency or memory frequency so there is a happy medium to be found based on the memory you are using. For instance my  bad 4770K will run 4.5Ghz all day long with 2400Mhz memory as long as the cache ring frequency stays a 4Ghz. If I drop the memory frequency to 2133 or reduce the core clock speed to 4400Mhz  I can bump the cache clock to 4200-4300. Core clock is king but the cache clock really helps when you push the limits.  

[Boinker]

I can answer you are in the right forum. Overclocking is Overclocking. Even if its a toaster or wifi router. Lol.

 

I had similar results with my older i7 920 where the most stable positions for uncore clock when at high clocks were the lowest or second lowest spot. But if i moved the uncore up to the third or forth from lowest, if it was stable, the processor low an behold more responsive. On that chip it was at least twice the dram frequency. Not sure what Haswell is requiring for its cache frequency but if it helps your system then do it. Judging by the layout it will help everything around the processor. You will not see much bench mark upgrades but if it helps in game to run a hotter cpu cache and is stable then do it.

 

So far as gpu. The sweet spot will be the highest core clockbut you can be stable enough to run and degrade performance at the same time. Fiddle with it in game and slowly raise the core clock and voltage until best results are achieved then up the memory until you get tearing and back it off a bit.

 

As far as monitoring the l1 l2 and l3 cache i can't say i have heard of such a thing. But maybe there is one out there. Just have to look around for it.

[ccokeman]

B) I'm running my GTX 780Ti at 1300Mhz, should there be a 'sweet spot' ratio to consider when playing with the VRAM clock?

 

 

Around 1900Mhz should do you well. 

[Waco]

It's almost always worthwhile to increase the uncore frequency, but like Frank said it's a balancing game. It can never really hurt you to increase it if everything else remains stable.

[MedievalNerd]

Why thank you everyone, got more information than I hoped for!

 

Just a few follow up questions.

 

When you some of you mentioned that there is some sort of tug of war bertween cache, core and ram could you elaborate? I wasn't aware of this and would like to know what are the guiding principals behind it. 

 

And thank you for the 1900Mhz VRAM Clock suggestion! I'll put it to good use.

 

I did have another sub question for you. I've been noticing that my GTX 780Ti is a bit finicky with what levels of voltages it will 'settle in'. When it reaches 1.212, even if I tell it to go to 1.225 (via the offsets of MSI Afterburner) it never really wants to bite. Back when I was using Precision X, I able to push it to 1.250, but it seems like it's stepping from 1.212 and 1.250. Is this 'normal' for some cards? Also, unlike Precision X seems the 'force voltage constant' option doesn't really to have any impact. It remains adaptive even if I turn it on. I'm thinking my card could go higher than 1300mhz, but the voltage levels are being very finicky.

This reminds me of the issues I was having when trying to puch my Cache Clock, the adaptive power setting didnt' give a poop that I would say it could go all the way to 1.25 or whatever setting, it would always stay below 1.0 and obviously my system would hang when trying to use Cache clock  higher than 3500mhz. I had to go the route of user voltages, and now that truly fixed the issues on that front. Is there a way to do this with videocards? It's running extremely cool all the time, (never goes above 50 celcius) so I don't care if I set it's GPU Voltage to a fixed 1.225 or 1.250 whatever I can make it stand at.

 

Thank you for all the help!


 

[GabrielT]

Make sure your not maxing your power limit, if your card is hitting the limit it may reduce voltage and clock speed to keep itself in spec. A modded bios can overcome this limit but the is often little gain.

 

Another reason could be temperatures, my 960 won't allow more than 1.23 if it is over 60c but if I crank up the fans it will go all the way up to 1.275 and boost the core clock to the moon.

[MedievalNerd]

Make sure your not maxing your power limit, if your card is hitting the limit it may reduce voltage and clock speed to keep itself in spec. A modded bios can overcome this limit but the is often little gain.

 

Another reason could be temperatures, my 960 won't allow more than 1.23 if it is over 60c but if I crank up the fans it will go all the way up to 1.275 and boost the core clock to the moon.

 

I am trailing the power limit, a meager 106% for the 780Ti, rather disappointing. I can live with 1300Mhz, but the fact that I know the card could go higher if it wasn't for the voltage capping it seems to run into, makes the speed demon inside me of scream in anger.

 

I'm sure it isn't temps, I have a full cover waterblock (VRM is also cooled) and the max temps even at 1300mhz are ~49celcius.

Edited June 3, 2015 by MedievalNerd

[GabrielT]

Well if you are comfortable moddifying and flashing your video cards bios that might solve your issues. Just don't blame me if you brick it searching for another 100mhz sometimes you just have to know when to quit.

 

 

You should check with gpu-z if you aren't already to make sure you afterburner is giving the extra voltage and just not showing it to you.

[ccokeman]

Why thank you everyone, got more information than I hoped for!

 

Just a few follow up questions.

 

When you some of you mentioned that there is some sort of tug of war bertween cache, core and ram could you elaborate? I wasn't aware of this and would like to know what are the guiding principals behind it. 

 

And thank you for the 1900Mhz VRAM Clock suggestion! I'll put it to good use.

 

I did have another sub question for you. I've been noticing that my GTX 780Ti is a bit finicky with what levels of voltages it will 'settle in'. When it reaches 1.212, even if I tell it to go to 1.225 (via the offsets of MSI Afterburner) it never really wants to bite. Back when I was using Precision X, I able to push it to 1.250, but it seems like it's stepping from 1.212 and 1.250. Is this 'normal' for some cards? Also, unlike Precision X seems the 'force voltage constant' option doesn't really to have any impact. It remains adaptive even if I turn it on. I'm thinking my card could go higher than 1300mhz, but the voltage levels are being very finicky.

 

This reminds me of the issues I was having when trying to puch my Cache Clock, the adaptive power setting didnt' give a poop that I would say it could go all the way to 1.25 or whatever setting, it would always stay below 1.0 and obviously my system would hang when trying to use Cache clock  higher than 3500mhz. I had to go the route of user voltages, and now that truly fixed the issues on that front. Is there a way to do this with videocards? It's running extremely cool all the time, (never goes above 50 celcius) so I don't care if I set it's GPU Voltage to a fixed 1.225 or 1.250 whatever I can make it stand at.

 

Thank you for all the help!

 

 

 

With Haswell they cay core clock is king but really like I said its a real balancing act. Try reading through the attached document as it has some good pointers and is based around the ASUS Rampage V Extreme but alot of the info translates.  Not sure what board you have but a list of system specs would help.

R5EOCGuide 2.pdf

[Boinker]

If it's an evga card then precision x works best and for some of the afterburner releases I Found on my dinosaur tyranasaurus 'rex 480s it would not let me get the full overvolt unless. Was using precision x.

[MedievalNerd]

 

Why thank you everyone, got more information than I hoped for!

 

Just a few follow up questions.

 

When you some of you mentioned that there is some sort of tug of war bertween cache, core and ram could you elaborate? I wasn't aware of this and would like to know what are the guiding principals behind it. 

 

And thank you for the 1900Mhz VRAM Clock suggestion! I'll put it to good use.

 

I did have another sub question for you. I've been noticing that my GTX 780Ti is a bit finicky with what levels of voltages it will 'settle in'. When it reaches 1.212, even if I tell it to go to 1.225 (via the offsets of MSI Afterburner) it never really wants to bite. Back when I was using Precision X, I able to push it to 1.250, but it seems like it's stepping from 1.212 and 1.250. Is this 'normal' for some cards? Also, unlike Precision X seems the 'force voltage constant' option doesn't really to have any impact. It remains adaptive even if I turn it on. I'm thinking my card could go higher than 1300mhz, but the voltage levels are being very finicky.

 

This reminds me of the issues I was having when trying to puch my Cache Clock, the adaptive power setting didnt' give a poop that I would say it could go all the way to 1.25 or whatever setting, it would always stay below 1.0 and obviously my system would hang when trying to use Cache clock  higher than 3500mhz. I had to go the route of user voltages, and now that truly fixed the issues on that front. Is there a way to do this with videocards? It's running extremely cool all the time, (never goes above 50 celcius) so I don't care if I set it's GPU Voltage to a fixed 1.225 or 1.250 whatever I can make it stand at.

 

Thank you for all the help!

 

 

 

With Haswell they cay core clock is king but really like I said its a real balancing act. Try reading through the attached document as it has some good pointers and is based around the ASUS Rampage V Extreme but alot of the info translates.  Not sure what board you have but a list of system specs would help.

 

Thanks for the doc, tried adding my system specs to my signature. But just in case it fails:

 

MB: ASUS X99-A

CPU: i7-5820k @ 4.5Ghz (Cache @ 4.0Ghz)

GPU: EVGA GTX 780Ti Superclocked @ 1300Mhz

Memory: G.Skill 16GB DDR4 2400mhz

PSU: AX760i

 

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