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Mosc_007 · ‎11-09-2014

As you may know I have been chasing a problem which has been causing a considerable drop in the Cinebench score when using a BCLK of 125 Mhz compared to using BCLK of 100 Mhz. My CPU Clock is 4.4 Ghz, Cache is on 4.0 Ghz and Ram is on 2666 Mhz.

I recently noticed when using 125 Mhz BLCK that the Cache Clock was only on 3.0 Ghz. Which is the default Turbo Cache Clock. It should have been on 4.0 Ghz as that is the Ratio I set in BIOS. I increased the Cache Ratio and it jumped up to 3.75 Ghz. I increased it one more point and it jumped up that high it wouldn't post.

I have done some more testing and I know whats happening now. I just tried to test again with the CPU at 4.5 Ghz and the Cache Ratio now works correctly. The same Cinebench score with 100 Mhz and 125 Mhz BCLK. I tried 4.5 Ghz as I can get two Ratio's that give exactly 4.5 Ghz at both 100 Mhz and 125 Mhz BCLK. And two Ratio's that give exactly 4.0 Ghz Cache Clock. Using a CPU Clock of 4.4 Ghz I can only get 4.375 Ghz with 125 Mhz BCLK so the test is not at the same CPU Clock at 100 and 125 Mhz BCLK..

The Cache Ratio actually works with CPU Ratio on 36 with 125 Mhz BCLK. But put the CPU Ratio on 35 with BCLK at 125 Mhz and it buggers up the Cache Ratio.

Reason:
When the CPU Ratio is on 35 with BCLK on 125 Mhz the BIOS is "Disabling" Turbo mode. Which doesn't effect the CPU clock as Speed step is off. But it drops the Cache back to 3.0 Ghz as thats the Default Cache speed. Putting other values for Cache Ratio and it just goes crazy. Jumps up to 3.75 Ghz then jumps up that high it wont even Post. No Idea what it tried to put it on.

I tried to Enable Turbo mode with CPU Ratio on 35 and BCLK of 125 Mhz and it then put the CPU Ratio back to Auto.

The BIOS won't allow Turbo mode with the CPU Ratio on 35 with 125 Mhz BCLK.

Is this a Bug in the BIOS ?

Or is their a reason why the BIOS disables Turbo mode with a CPU Ratio on 35 when using a 125 Mhz BCLK ?

But a CPU Ratio of 36 with 125 Mhz and Turbo mode works.

Charles

Chino · ‎11-09-2014

No, it's not a bug with the BIOS. Perhaps you're not modifying the correct values.

The Cache frequency will reflect whatever value you set provided that your CPU is able to run cache that high.

CPU and cache both at 4.375GHz using the 35 Ratio and 125 Strap.

Mosc_007 · ‎11-09-2014

OK. But with Turbo mode disabled the Cache won't go above 3.0 Ghz. I am trying to run the Cache at 4.0 Ghz and the CPU at 4.375 Ghz with 125 Mhz BCLK.

When I try to use a CPU Ratio of 35 with 125 Mhz BCLK the Bios is disabling Turbo Mode. If i try to turn Turbo mode back on then the BIOS changes the CPU Ratio to Auto. If change the CPU Ratio back 35 the Bios turns off Turbo mode again. But with CPU Ratio of 36 it all works. Nothing else is changed. Just CPU Ratio of 35 or 36.

I assume you are running 0802 BIOS. Maybe this is only a problem with 0706. I will update the BIOS tonight and see if it works.

I had another totaly crazy problem happen on Boot last night. It had been off all day. Nothing changed in the BIOS. It was booting and the speaker beeped a few times. When the screen came up it had a warning that the CPU Vcore was too High. It then took me into BIOS. The Vcore was still set on 1.280 as it always has been but the Bios was showing their was 1.7 Volts on the CPU. I just rebooted and it was all ok. I realy hope the Bios didn't put 1.7 Volts on the CPU Cores. It has only ever happened the once.

Charles

Mosc_007 · ‎11-10-2014

I just installed BIOS 0802. Cleared CMOS after loading and put my settings back in.

Exactly the same problem. When I try to get a CPU Clock of 4.375 and a Cache Clock of 4.0 Ghz with a BCLK of 125 Mhz the BIOS is disabling Turbo mode making the Cache run at 3.0 Ghz. CPU is running at 4.375 Ghz Though.

Here is my main BIOS settings. Please see if I have missed anything Obvious.

In the Bios you can see the Max Cache Ratio is on 32. Which should give 4.0 Ghz. 32 X 125 = 4000 Mhz

But in the ROG CPU-Z you can see it's only on 3.0 Ghz.

Any idea what I am missing ?

Same as BIOS 0706. If I set the CPU Ratio to 36 then Turbo mode is enabled and the Cache is on 4.0 Ghz.

Charles

Praz · ‎11-10-2014

Hello

Monitor the cache speed with the system under full load. Or set both min and max to the same value. There is no advantage attempting to downclock the cache speed with a fully manual set cache voltage.

Mosc_007 · ‎11-10-2014

I have speed step dissabled so the CPU is on max clock all the time. I checked the Cache speed while cinebench was running and it stayed on 3.0 Ghz. I assume its doing that because the BIOS is dissabling Turbo mode with CPU ratio on 35. But if I change the CPU ratio to 36 then the BIOS is enableing Turbo mode and CPU-Z is showing cache is on 4.0 Ghz.

Do you know why the BIOS is dissableing Turbo mode with CPU ratio on 35 with BCLK at 125 Mhz but it enables Turbo mode if I use a CPU ratio of 36 ?

Chino has posted screen shots with it working but his Cache Ratio is different to mine.

Charles

Praz · ‎11-10-2014

Hello

The Turbo setting is for set multipliers higher than stock. A 35 multiplier is stock so Turbo is not needed.

Mosc_007 · ‎11-10-2014

Sounds fair enough. Problem is that when Turbo mode is off the Cache drops to 3.0 Ghz no matter what Ratio I set in the BIOS.

Does explain why Chino's is working. The default clock on the 5960x is lower than the 5930k. So his Turbo is on at a ratio of 35.

Thanks for your help. It all makes sense now. Even though the CPU is actualy over clocked with a ratio of 35 using 125 Mhz BCLK the BIOS thinks its not so it turns Turbo mode off.

Charles

Praz · ‎11-10-2014

Hello

You're welcome. 🙂

Possable BIOS 0706 bug