ASRock Extreme 4 w/1.80 bios showing incorrect max turbo speed in bios

[jarablue]

Just built the system today. ASRock Extreme 4 with 4790k. In the bios settings the max default speed is 4000 and the max turbo speed is 4000. Updated the board out of the box. CPUZ, windows task manager show that I'm getting 4.4 -4k no problem but the bios isn't showing this.

Is this a bug? My first post, hi everyone. :)

[parsec]

Re: ASRock Extreme 4 w/1.80 bios showing incorrect max turbo speed in bios

Just built the system today. ASRock Extreme 4 with 4790k. In the bios settings the max default speed is 4000 and the max turbo speed is 4000. Updated the board out of the box. CPUZ, windows task manager show that I'm getting 4.4 -4k no problem but the bios isn't showing this.

Is this a bug? My first post, hi everyone. :)

Welcome to the Tweak Town forum!

Be careful just using just "Extreme 4" (really "Extreme4") as the name of your board. ASRock currently has 10 boards that have "Extreme4" in their name, and there are others no longer produced that use that term too. ASRock > Motherboard Series

I can tell you have a Z97 Extreme4 board from your CPU and BIOS version.

The apparent mistake in the display of the CPU speeds you see in the OC Tweaker screen is generally as you described it, but lets take another look:



What you are seeing in the OC Tweaker screen are the Target CPU Turbo Speed and Target CPU Cache speed. Since the CPU Cache Speed is normally the same as the non-Turbo maximum CPU speed, the displayed values would be the same. That does not make your observation of an incorrect Target CPU Turbo speed apparently being displayed to be wrong. The displayed values need some explanation, and then we can decide if the Target CPU Turbo Speed value is incorrect.

If CPU Ratio is set to Auto, then the ratio (multiplier) for all cores is "set" (more on this later) to produce the processor base frequency value for the processor used in the board. In your case that is a ratio of 40, for a speed of 4000MHz. The ratio for every core is set to 40 in the BIOS. My CPU's base frequency ratio is 36, so the speed is 3600MHz.

If CPU Ratio is set to All Cores, with the default ratio value unchanged, you'll see a display of the same values as Auto.

If CPU Ratio is set to Per Core, with the default values unchanged, you'll see the display of the Target CPU Turbo Speed and Target CPU Cache speed change to 4000MHz and 4400MHz. In this case the ratio for each core is set individually, up to the true Turbo speed ratio of 44. But these ratio settings are not what is needed for Turbo to work, as you have seen.

The problem is while you see your CPU operates at 4.4GHz in Windows, the BIOS shows a max Turbo speed of 4.0GHz. The max Turbo speed shown in the BIOS is wrong when the CPU is set to its stock speed.

There is a problem with the Target CPU Turbo Speed when the CPU is set to its stock speed, it should NOT depend on what the CPU ratios are set to. When the CPU Ratio option is set to Auto, which is a non-over clocked, stock speed setting, the Turbo speed does not depend on the ratio/multiplier settings in the BIOS, it happens automatically within the CPU itself. The CPU changes the core ratios up to the max Turbo speed, beyond the values in the BIOS.

Things change when the CPU is over clocked. When the CPU ratios are set to over clocked values, which are any values beyond the processor's base speed, Turbo no longer works in the same way as it does when the using stock CPU speed.

For example, if Turbo worked in the same way when the CPU is over clocked, the CPU's speed would increase beyond the over clocked core ratios. If you set your core ratios to 45, which results in an over clocked CPU speed of 4.5GHz, Turbo would boost the speed beyond that, to 4.9GHz, assuming the same amount of Turbo boost (4.0 to 4.4GHz, or four steps of the CPU ratio) is applied. That does not happen.

The error is in the way the Target CPU Turbo Speed is calculated. It is done using only the CPU core ratios values. That is correct when the CPU is over clocked. It is not correct when the CPU is set to its stock speed.

So, good call on the Target CPU Turbo Speed being incorrect, but it is only incorrect when the CPU operates at its stock speed. That does not mean it doesn't matter.

Why has this not been noticed before now? It may have been by some people, but usually people that do not over clock don't pay close attention to things in the BIOS. People that over clock are not using stock processor settings and speed, so they see the correct Target CPU Turbo Speed being displayed. IMO, it could be argued that once a processor is over clocked, its speed is actually not a "CPU Turbo Speed", but that is another subject.

I did not pay attention to this problem myself, since I usually over clock, and verify the OC in Windows. I have not checked the BIOS of my other ASRock boards, models older than my Z97 board, but my guess is they are the same. I'll check and report back in this thread.

Great first post here, you're putting me to shame about not noticing this myself. Unless there is another explanation, but I've thought about this for a while now, and I really believe you are right.

[jarablue]

Re: ASRock Extreme 4 w/1.80 bios showing incorrect max turbo speed in bios

Well thanks so much! Your post was informative as heck. Your right, I should of said Z97 Extreme4. Sorry about that. I appreciate you looking into it. The board is pretty good and works fine. Maybe in a new bios .rev that change will made.

Again thanks for taking the time to explain it to me.