[SOLVED] i7-4790S refusing to turbo ?

[Budgeteer_262]

Hi,

I have an i7 4790S on a B85M-E motherboard and I'm trying to get all 8 threads (4 cores) to turbo to the max 4Ghz possible for this non-k cpu.

In the bios I've tried:

Synchronising all core speeds with 4Ghz max turbo
Disabling intel speedstep
Setting long duration power to 84W (the tdp of the non-s variant)
Setting Core voltage to 1.10

When running Prime95 stress test, all cores immediately go to 3600Mhz and then after a minute all go to 3200Mhz (3200Mhz because it's an s sku cpu). I'm trying to get them to go to 4000Mhz.

I have a fin stack style cooler with a push-pull fan configuration and fresh thermal paste. The system idles at around 23 (72F) degrees Celsius and settles at around 66 (151F) degrees Celsius under Prime95 synthetic workload so I don't think its thermal throttling.

Is there a silver bullet bios setting on my asus motherboard I can use to fix this?

Thanks

 

[helpstar]

disable all "tuning" values and try again using default settings
this should get you 3.6GHz all the time, if not, something is odd

 

[Karadjgne]

The i7-4790S is a locked cpu, and stands a good chance of not being on a Z rated motherboard. So you'll only get whatever Intel has designated as Turbo per core amount. Which means 4.0/3.9/3.9/3.8GHz for the 1/2/3/4 core loads. Disable Turbo should reach the default base of 3.6GHz all core.

You'll not get 4.0GHz on all cores as that's the single core maximum, not All core maximum.

 

[Budgeteer_262]

If intel has locked the four core limit to 3.8 as I think you said, why is my cpu at 3.6 and not 3.8 when under synthetic loads at 55-65 degrees Celsius ? Is that because it is an s sku? I thought that the only difference on the s sku is that it can clock down to 3.2?

Also, I do get 4ghz on multiple threads at the same time. Just never under synthetic load. Will try default settings and no “optimisations” and will get back to you.

thanks for the responses so far

 

[kerberos_20]

If intel has locked the four core limit to 3.8 as I think you said, why is my cpu at 3.6 and not 3.8 when under synthetic loads at 55-65 degrees Celsius ? Is that because it is an s sku? I thought that the only difference on the s sku is that it can clock down to 3.2?

Also, I do get 4ghz on multiple threads at the same time. Just never under synthetic load. Will try default settings and no “optimisations” and will get back to you.

thanks for the responses so far

3.8ghz is at 4 core load, syntetic tests runs at all core, you can set affinity for 4 cores for that syntetic workload

 

[TerryLaze]

If intel has locked the four core limit to 3.8 as I think you said, why is my cpu at 3.6 and not 3.8 when under synthetic loads at 55-65 degrees Celsius ?

Yeah 7 and 8 threads are going to be 3.6Ghz on the S model.
I think you need a Z board to make it run MCE and get higher all core clocks.

Performance-Optimized: Core i7 4790 vs Core i7 4790S

You may be familiar with Intel naming their processors under the Core i7, i5 and i3 moniker based on the performance and features offered. But beyond that...

www.techspot.com

 

[Budgeteer_262]

3.8ghz is at 4 core load, syntetic tests runs at all core, you can set affinity for 4 cores for that syntetic workload

Do I need to? I only have 4 cores?

 

[Budgeteer_262]

Yeah 7 and 8 threads are going to be 3.6Ghz on the S model.
I think you need a Z board to make it run MCE and get higher all core clocks.

Performance-Optimized: Core i7 4790 vs Core i7 4790S

You may be familiar with Intel naming their processors under the Core i7, i5 and i3 moniker based on the performance and features offered. But beyond that...

www.techspot.com

Thanks for the insight. When the 4 core limit is 3.6, does that mean that all cores except 1 are above 3.6 and just one is at 3.6?

 

[Budgeteer_262]

And do both of the threads assigned to 1 core have to run at the same frequency?

 

[Karadjgne]

Cores run concurrent, not consecutive. So when playing CSGO, which is a 2 core load, you'll be at 3.9GHz. It's only when running single core loads that you'll see 4.0GHz. But anything less than a full core load is somewhat misleading if you only look at the cpu speed, as it'll give you the current highest speed and temp, not the actual core loads and temps.

 

[Budgeteer_262]

ok, thanks for clarifying