AMD Kaveri Refresh A10-7870K Apu arrives. - Page 33 - Overclock.net - An Overclocking Community

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AMD Kaveri Refresh A10-7870K Apu arrives.

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post #321 of 537 (permalink) Old 07-03-2015, 08:08 PM
 
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After a bit of tweaking this is what I managed to get- http://www.3dmark.com/3dm11/9994746
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post #322 of 537 (permalink) Old 07-04-2015, 02:35 AM - Thread Starter
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Quote:
Originally Posted by MatrixDecker View Post

I just replaced an Athlon 750K with a A10-7870K on a Gigabyte G1.Sniper A88X and I'm experiencing system lock-ups whenever I try to undervolt the APU using AMD Overdrive (it freezes even on [email protected]). I would have used the BIOS setting if negative offsets were allowed, but they are not.

I assumed, looking at the Sniper BIOS screens, that voltage adjustments work on absolute values: that you use the +/- keys from the numeric pad to gain control over the [Auto] box, set the current value you got from the Status Screen, use the +/- keys to set your target and then repost. But you're saying it doesn't work like that?

Until you have your OC sorted out I would put your Raijintek Themis back and leave cooling the VRMs to your case fans. The Themis has clearance underneath its fins which the stock cooler doesn't have, so is actually less restrictive of the airspace around the VRMs.

While you're doing that you can check your TIM, because your APU is behaving like your cooler isn't working properly.
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post #323 of 537 (permalink) Old 07-04-2015, 03:22 AM
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The VRM controller on A88X Sniper (ISL6377) doesn´t support voltage offsets, outside the AMD load-line compensation.
Only VID based adjustment is possible, ie. fixed voltage.

The only proper way to undervolt on this motherboard is to change the VID commands issued in different PStates.
For that purpose you´ll need a software which is able edit the PState MSR registers (MSRTweaker or such).

AOD is badly outdated, obsolete and should not be used on any products newer than K10.
Regardless, it cannot modifiy individual PStates.

For APUs having a digital VRM controller is pretty much mandatory if you like to fiddle around (either undervolt or overclock properly).
IR digital controllers can be found in most ASUS FM2+ boards, Gigabyte UP4 and in certain ASRock boards. Lower-end ASUS boards use simpler
UPI digital controller with more limited adjustments, however the basic controls such as voltage offsets and load-line adjustment are supported in better extent than the specification requires.
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post #324 of 537 (permalink) Old 07-04-2015, 08:27 AM
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Quote:
Originally Posted by Himo5 View Post

I assumed, looking at the Sniper BIOS screens, that voltage adjustments work on absolute values: that you use the +/- keys from the numeric pad to gain control over the [Auto] box, set the current value you got from the Status Screen, use the +/- keys to set your target and then repost. But you're saying it doesn't work like that?

Until you have your OC sorted out I would put your Raijintek Themis back and leave cooling the VRMs to your case fans. The Themis has clearance underneath its fins which the stock cooler doesn't have, so is actually less restrictive of the airspace around the VRMs.

While you're doing that you can check your TIM, because your APU is behaving like your cooler isn't working properly.

I have managed to use your data (excellent information) on default P-State voltages for 7850K and 7870K to get a "default 7850K" undervolt with AMD MSR Tweaker, and so far it it's working great. I'll be putting back the Termis because the stock 7870K cooler is not enough to cool the CPU in BIOS! It goes to 60 degrees pretty fast, and I did not stick around to find out how far it will go. I'm going to use IBT AVX to test for stability for each individual P-State with a bit of additional underclock (similar to how you made the minimal voltage tables, another great source of information)

TIM is Noctua NT-H1 and was applied properly. I have an extra 70 mm fan to mount in the VRM area to give a bit more airflow over the VRMs
Quote:
Originally Posted by The Stilt View Post

The VRM controller on A88X Sniper (ISL6377) doesn´t support voltage offsets, outside the AMD load-line compensation.
Only VID based adjustment is possible, ie. fixed voltage.

The only proper way to undervolt on this motherboard is to change the VID commands issued in different PStates.
For that purpose you´ll need a software which is able edit the PState MSR registers (MSRTweaker or such).

AOD is badly outdated, obsolete and should not be used on any products newer than K10.
Regardless, it cannot modifiy individual PStates.

For APUs having a digital VRM controller is pretty much mandatory if you like to fiddle around (either undervolt or overclock properly).
IR digital controllers can be found in most ASUS FM2+ boards, Gigabyte UP4 and in certain ASRock boards. Lower-end ASUS boards use simpler
UPI digital controller with more limited adjustments, however the basic controls such as voltage offsets and load-line adjustment are supported in better extent than the specification requires.

Since I started using AMD Msr Tweaker I had almost no problems at all. Today I'm determining custom P-State settings for normal use. I'll spread the top normal P-States a bit, something like this:
P0 - 3900 -> 4200
P1 - 3800 -> 4000

I'm considering getting a Crossblade Ranger. It's on sale right now, but still one of the most expensive FM2+ boards around at about 120 Euro. However, the FM2+ platform does not have better CPUs in the pipeline, and I'll probably wait for the AM4 platform.

To get around excessive power use in BIOS, I'll downclock the CPU to about 3500.

That you both for excellent information.

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post #325 of 537 (permalink) Old 07-04-2015, 12:42 PM - Thread Starter
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I saw someone earlier in the thread struggling to put together a coherent OC path for memory and it has suddenly reminded me of my first brush with G.Skill TridentX and the solution I found for it in Ocaholic Reviews.

It is actually worthwhile using that list of their reviews as a buying guide, because each Review produces a version of the following chart on its 'Results' page, and although they are really about the relationship between ram and the Intel processors many of them are tested with, they still provide enough information about the margins within which it is worth experimenting.


My following adaptation of the original chart provided many successful overclocks with the 2x4Gb 2400MHz kit I started with and still use.
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post #326 of 537 (permalink) Old 07-04-2015, 07:29 PM
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Quote:
Originally Posted by Himo5 View Post

I saw someone earlier in the thread struggling to put together a coherent OC path for memory and it has suddenly reminded me of my first brush with G.Skill TridentX and the solution I found for it in Ocaholic Reviews.

It is actually worthwhile using that list of their reviews as a buying guide, because each Review produces a version of the following chart on its 'Results' page, and although they are really about the relationship between ram and the Intel processors many of them are tested with, they still provide enough information about the margins within which it is worth experimenting.


My following adaptation of the original chart provided many successful overclocks with the 2x4Gb 2400MHz kit I started with and still use.
that would be me. It was the fault of the micro center exclusive memory by EVGA, the ASRock killer board doesn't like it

i-7 6700k @4.2GHZ, 16 GIGS DDR4 3200 Corsair Vengence, Gigabyte Gaming 7 Z-170X, Coolmaster Hyper 212 EVO, EVGA SSC GTX 970, 2x 500GIG WD Raid 0, Corsair CX 750 PSU, Corsair Air 540 Case, Windows 10 PRO 64bit.
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post #327 of 537 (permalink) Old 07-05-2015, 04:42 AM
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All Kaveri / Godavari parts are able to run at 2400MHz MEMCLK as long as the settings are correct.
It should require no additional VDDNB voltage either, unless your chip is running extremely hot. To ensure stability in all conditions I would recommend using the default voltage together with 80% or 60% load-line adjustment.

On boards which feature an advanced VRM controller (IR356x) it is important NOT to use the fixed voltage mode.
This is because the output voltage feeds two different domains, with two different voltage level requirements; CNB has default voltage < 1.1250V while the GNB always defaults to 1.225V (KV) or 1.275V (GV) in 3D. If you enable the fixed voltage mode and set it to eg. 1.150V you will most likely have no issues on desktop, but in 3D the GPU might potentially crash due undervoltage. Likewise if you set the fixed voltage to e.g. 1.2750V, you will just end up wasting power on the desktop when the GPU is not used. When the fixed voltage option is used the VID commands issued by any of the domains (CPU, CNB, GNB) are completely ignored. As the name indicates, the voltages are fully fixed.

When using unofficially supported MEMCLK (i.e. 2400MHz) most ODMs automatically add a voltage offset to the VDDNB voltage. In most cases the automatic voltage offset is way too large and it only results in excessively high power consumption with no additional stability. In fact in some cases the automatic voltage offset is so high that the resulting output voltage violates AMD´s electrical specifications, and potentially can cause instability or even degradation. To ensure there is no excessively high automatic voltage offset added by the bios, you must ensure that the offset voltage is NOT set to Auto. If you are adjusting either CPU, NCLK, GPU or MEMCLK frequencies above their default level you should use at least 0.00625V offset voltage (±, doesn´t matter). Setting the offset value to anything other than Auto will prevent the bios from using the automatic voltage offsets.

Overclocking the APUs has always been extremely tricky since adjustments made to one domain also affect the other.

Kaveri / Godavari will not be able reach MEMCLKs higher than 2400MHz, and the reason for this limitation is rather simple.
During the boot the memory controllers perform a calibration process dubbed as training. The training process will adjust the settings until the signal patterns match the predefined pattern for the set memory frequency. The memory controllers perform training at several different frequencies depending on the desired memory clocks. For example when the desired MEMCLK is 2133MHz the memory training will be performed at 800, 1066, 1333, 1600, 1866 and 2133MHz frequencies. The memory signals can drift from their trained settings only so slightly without causing any problems. If the actual signaling changes to either direction, at some point it will either result in memory errors or system crash depending on how much apart the signaling is and how many errors are produced because of it.
This is the reason why using 110MHz BCLK with 3:28 (1866MHz) MEMCLK ratio (= 2053MHz) might be unstable while the 3:32 (2133MHz) MEMCLK ratio at 100MHz BCLK works just fine.

The memory controller in Kaveri / Godavari cannot train the memory for any frequency higher than 2400MHz.
You can try to reach higher frequencies by increasing the BCLK frequency from 100MHz, however in that case you are playing with the signal margins which is never advised for the sake of stability.
Regardless how much you increase the BCLK above the default 100MHz value, the memory will not be trained for any other frequency but 2400MHz. That´s why anything higher than 2400MHz will not be reliable or stable, no matter how much you fool around with the voltages or timings.

These limitations will apply regardless of the motherboard as the limitation is purely in the memory controller.
Some motherboards might have slightly shorter trace lengths, larger trace spacing or cleaner supply for VDDIO or the reference voltages, but the difference between the designs will still be non-existent due the limitations set by the memory controller itself.

To maximize the memory performance and stability on Kaveri / Godavari, use following configuration:

- Two DRAM modules
- Dual rank modules (two sided with 8 ICs on each side)
- Hynix CFR (2Gb), MFR (4Gb) or Samsung D-Die (2Gb) or Q-Die (4Gb)
- Micron / Elpida and Nanya ICs are usually good for 1600-1866MHz on AMD

The penalty from using single rank modules is worth around one speed class or 133MHz (2400MHz SR = 2133MHz DR, 2133MHz SR = 1866MHz DR).

On average (depending on leakage) the GPU reaches it´s maximal frequency with 1.27 - 1.30V actual.
In most cases the GPU and NCLK frequency scaling starts to show retardation if the voltage is raised beyond that.
The CNB/GNB voltage scaling is rather poor in Kaveri / Godavari, so trying to reach frequencies beyond the linear scaling curve by using excessively high voltage is futile and after a certain point dangerous to the silicon. Unless the iGPU is (for some odd reason) used for computing, overclocking the iGPU is rather pointless as at 2400MHz MEMCLK there is not enough of bandwidth to keep the GPU fully fed even at 600MHz.

The breakdown (absolute maximum) voltage for Kaveri / Godavari CNB/GNB (VDD_NB) is 1.320V.
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post #328 of 537 (permalink) Old 07-05-2015, 01:32 PM
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Is this CPU able to run League, Maplestory, CSGO, & Tomb Raider? Do some about 3 times a week photo editing using Photoshop and Light Room?

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post #329 of 537 (permalink) Old 07-05-2015, 02:57 PM
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Originally Posted by AOMG View Post

Is this CPU able to run League, Maplestory, CSGO, & Tomb Raider? Do some about 3 times a week photo editing using Photoshop and Light Room?
CS:GO is not a problem for the cpu at all, the igpu should be more than enough too, at least if its overclocked :-)

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post #330 of 537 (permalink) Old 07-05-2015, 04:38 PM - Thread Starter
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Quote:
Originally Posted by The Stilt View Post

All Kaveri / Godavari parts are able to run at 2400MHz MEMCLK as long as the settings are correct.
It should require no additional VDDNB voltage either, unless your chip is running extremely hot. To ensure stability in all conditions I would recommend using the default voltage together with 80% or 60% load-line adjustment.

On boards which feature an advanced VRM controller (IR356x) it is important NOT to use the fixed voltage mode.
This is because the output voltage feeds two different domains, with two different voltage level requirements; CNB has default voltage < 1.1250V while the GNB always defaults to 1.225V (KV) or 1.275V (GV) in 3D. If you enable the fixed voltage mode and set it to eg. 1.150V you will most likely have no issues on desktop, but in 3D the GPU might potentially crash due undervoltage. Likewise if you set the fixed voltage to e.g. 1.2750V, you will just end up wasting power on the desktop when the GPU is not used. When the fixed voltage option is used the VID commands issued by any of the domains (CPU, CNB, GNB) are completely ignored. As the name indicates, the voltages are fully fixed.

When using unofficially supported MEMCLK (i.e. 2400MHz) most ODMs automatically add a voltage offset to the VDDNB voltage. In most cases the automatic voltage offset is way too large and it only results in excessively high power consumption with no additional stability. In fact in some cases the automatic voltage offset is so high that the resulting output voltage violates AMD´s electrical specifications, and potentially can cause instability or even degradation. To ensure there is no excessively high automatic voltage offset added by the bios, you must ensure that the offset voltage is NOT set to Auto. If you are adjusting either CPU, NCLK, GPU or MEMCLK frequencies above their default level you should use at least 0.00625V offset voltage (±, doesn´t matter). Setting the offset value to anything other than Auto will prevent the bios from using the automatic voltage offsets.

Overclocking the APUs has always been extremely tricky since adjustments made to one domain also affect the other.

Kaveri / Godavari will not be able reach MEMCLKs higher than 2400MHz, and the reason for this limitation is rather simple.
During the boot the memory controllers perform a calibration process dubbed as training. The training process will adjust the settings until the signal patterns match the predefined pattern for the set memory frequency. The memory controllers perform training at several different frequencies depending on the desired memory clocks. For example when the desired MEMCLK is 2133MHz the memory training will be performed at 800, 1066, 1333, 1600, 1866 and 2133MHz frequencies. The memory signals can drift from their trained settings only so slightly without causing any problems. If the actual signaling changes to either direction, at some point it will either result in memory errors or system crash depending on how much apart the signaling is and how many errors are produced because of it.
This is the reason why using 110MHz BCLK with 3:28 (1866MHz) MEMCLK ratio (= 2053MHz) might be unstable while the 3:32 (2133MHz) MEMCLK ratio at 100MHz BCLK works just fine.

The memory controller in Kaveri / Godavari cannot train the memory for any frequency higher than 2400MHz.
You can try to reach higher frequencies by increasing the BCLK frequency from 100MHz, however in that case you are playing with the signal margins which is never advised for the sake of stability.
Regardless how much you increase the BCLK above the default 100MHz value, the memory will not be trained for any other frequency but 2400MHz. That´s why anything higher than 2400MHz will not be reliable or stable, no matter how much you fool around with the voltages or timings.

These limitations will apply regardless of the motherboard as the limitation is purely in the memory controller.
Some motherboards might have slightly shorter trace lengths, larger trace spacing or cleaner supply for VDDIO or the reference voltages, but the difference between the designs will still be non-existent due the limitations set by the memory controller itself.

To maximize the memory performance and stability on Kaveri / Godavari, use following configuration:

- Two DRAM modules
- Dual rank modules (two sided with 8 ICs on each side)
- Hynix CFR (2Gb), MFR (4Gb) or Samsung D-Die (2Gb) or Q-Die (4Gb)
- Micron / Elpida and Nanya ICs are usually good for 1600-1866MHz on AMD

The penalty from using single rank modules is worth around one speed class or 133MHz (2400MHz SR = 2133MHz DR, 2133MHz SR = 1866MHz DR).

On average (depending on leakage) the GPU reaches it´s maximal frequency with 1.27 - 1.30V actual.
In most cases the GPU and NCLK frequency scaling starts to show retardation if the voltage is raised beyond that.
The CNB/GNB voltage scaling is rather poor in Kaveri / Godavari, so trying to reach frequencies beyond the linear scaling curve by using excessively high voltage is futile and after a certain point dangerous to the silicon. Unless the iGPU is (for some odd reason) used for computing, overclocking the iGPU is rather pointless as at 2400MHz MEMCLK there is not enough of bandwidth to keep the GPU fully fed even at 600MHz.

The breakdown (absolute maximum) voltage for Kaveri / Godavari CNB/GNB (VDD_NB) is 1.320V.

Phew! Rep+

So when I turned off C6, CNB and PowerNow and set CPU Voltage Mode to Manual in BIOS and then ran a series of P95 sessions at various CPU Voltages set in AI Suite III, 3700-4700MHz, it was a good job I had ram at 1866MHz and wasn't pushing the iGPU? And an overclock based on a high BClk, like the following would be inherently unstable because of the high BClk?


I wonder, however, if ram that has an XMP higher than 2400MHz, like this 2x4Gb 2666MHz Cas11 kit somehow escapes the process, since I have run it with Godavari over 2400MHz without problems, as this Memtest86 screen implies:
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