AMD Kaveri Refresh A10-7870K Apu arrives. - Page 7 - Overclock.net - An Overclocking Community

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AMD Kaveri Refresh A10-7870K Apu arrives.

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post #61 of 532 (permalink) Old 05-28-2015, 12:29 PM
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Quote:
Originally Posted by drmrlordx View Post

Right. It's just that some of the newer SKUs are also using the older stepping, at least for now. Should be interesting to see if the new Athlon x4 is JC/GV-A1.

I can confirm that the 7870k has "gone live" at major etailers. Newegg has them in stock:

http://www.newegg.com/Product/Product.aspx?Item=N82E16819113393

I haven't seen the 7670k yet.

After some time the "Godavari" die will be no doubt used in older models too, however the model number will remain the same (JA / "KV-A1").
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post #62 of 532 (permalink) Old 05-28-2015, 12:39 PM
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Roger, why is VID so high with 7870K? Its bad BIOS autosettings (old agesa)?

Ryzen Threadripper TBD ,-), Ryzen Threadripper 1950X, Ryzen 7 2700X, Ryzen 5 2400G, Ryzen 7 1800X, Ryzen 7 1700X, Ryzen 5 1500X, Ryzen 5 1600X, FX-8320E, FX-8370, FX-8370E, 2x FX-9590, 4x AMD FX-8350, 2x FX-8320, 2xFX-8300, 4xAMD FX-8150, AMD FX-8120 95W, AMD FX-8120 125W, AMD Phenom II x6 1100T BE, AMD Phenom II x6 1090T BE 4.3 GHz stable, AMD Phenom II x 980 BE, Phenom II x4 975 BE,Phenom II x4 970 BE, 2x Phenom II x4 965 BE C3, Phenom II x4 965 BE C2, Athlon 860K, Athlon 845, A10-7870K, 2xA10-7850K, 2x A10-7700K, A10-6800K, A10-6800B, A8-6600K, A10-5800K, A8-5600K, A10-3870K, A8-3850, Athlon 5150 Kabini,Intel core i9-7900X, Intel core i7-6950X, Intel core i7-5960X, core i7-3930K, i7-980X,3x Intel core i7-8700K, i7-7700K,i3-7350K, 2x i7-6700K, i5-6600K, i7-4770K, i7-3770K, i7-2600K
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post #63 of 532 (permalink) Old 05-28-2015, 01:40 PM
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Based my own tests on several different types of "Godavari silicon" the 7870K´s do indeed overclock better than Kaveri.
For the CPU part the average difference is around 300MHz, 200MHz for the CNB part and around 100MHz for the GPU.
The absolute clock ceiling for the CPU will be around the same (< 4800MHz) as it is process limited but Godavari will be able to do the same clocks as Kaveri with significantly less voltage.

The average clocks you can expect with a high-end motherboard and cooling are up to 4500 - 4700MHz for the CPU, 2100 - 2200MHz for CNB and 1040 - 1114MHz for the GPU. Compatible (Samsung or Hynix based) memory should run stable at 2400MHz without even touching the UNB voltage (CNB/GNB).

Both Kaveri and Godavari are extremely sensitive to fluctuations in CPU core voltage.
Since Godavari clocks higher than Kaveri it is even more sensitive to the fluctuations as the tolerance decreases at higher frequencies.
For that reason the load-line must be calibrated extremely accurately. At higher clocks you want the core voltage to stay within 15mV of the set-point even during the maximum loadstep. Both undershoot (droop) and overshoot hurt equally so simply maxing out the load-line control is not advised. Usually the -60% setting works the best.

Due the sensitivity to both voltage stability and other voltage characteristics the VRM plays a huge role when these parts are overclocked.
On a high-end motherboard with a digital VRM on it a chip might do 4.7GHz with just 1.45V. On a different lower-end motherboard the same chip might require 1.5V for 4.5GHz and be unable to reach any higher in otherwise identical conditions.

The CPU frequency usually reaches it´s peak at 1.45V - 1.475V depending on leakage.
It will accept higher voltage but usually the returns are non-existent. There is absolutely no point in trying to force the chip to do higher than xMHz if it requires more than 1.475V (actual).

The default voltages on 7870K´s are extremely high but also extremely conservative at the same time.
This means that there is a huge amount of undervolting potential in these chips. Not just for the CPU but for the UNB also.
On average the CPU requires around 200mV less voltage (abs. 1.2 - 1.25V) for the base frequency of 3.9GHz than the factory values indicate.
For the UNB the number is around 125mV (abs. 1.150V)

The power savings from undervolting are quite impressive.
The measurements are DCR (current over inductors) meaning they represent the actual power consumed by the APU.

Stock vs. Tuned voltages:

Pb0 (4100MHz) = 1.43750V vs. 1.1960V
P0 (3900MHz) = 1.38750V vs. 1.1530V
P1 (3800MHz) = 1.35000V vs. 1.1180V
P2 (3700MHz) = 1.30000V vs. 1.0960V
P3 (3500MHz) = 1.23750V vs. 1.0640V
P4 (3000MHz) = 1.08750V vs. 0.9630V
xx
xx

GNB (CNB + GNB) during 3D = 1.27500V vs. 1.0480V

Test: 3DMark11 Performance

Stock PMax VDD_CR DCR = 52.125W
Stock PMax VDDNB_CR DCR = 47.6875W
Total = 99.8125W

UV PMax VDD_CR DCR = 36.250W (-30.46%)
UV PMax VDDNB_CR DCR = 35.625W (-25.3%)
Total = 71.875W (-28%)

Test: 3DMark Sky Diver

Stock PMax VDD_CR DCR = 55.125W
Stock PMax VDDNB_CR DCR = 48.625W
Total = 103.75W

UV PMax VDD_CR DCR = 36.8125W (-33.21%)
UV PMax VDDNB_CR DCR = 37.1875W (-23.52%)
Total = 74.0W (-28.7%)

Test: 3DMark Fire Strike

Stock PMax VDD_CR DCR = 47.750W
Stock PMax VDDNB_CR DCR = 46.760W
Total = 94.51W

UV PMax VDD_CR DCR = 32.3125W (-32.33%)
UV PMax VDDNB_CR DCR = 35.000W (-25.15%)
Total = 67.3125W (-28.8%)

Test: Cinebench R15

Stock PMax VDD_CR DCR = 61.0625W

UV Pmax VDD_CR DCR = 35.6875W (-41.6%)



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post #64 of 532 (permalink) Old 05-28-2015, 03:18 PM
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@ the stilt:

What where the scores of those test/benches?

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post #65 of 532 (permalink) Old 05-28-2015, 03:30 PM
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Quote:
Originally Posted by DannyDK View Post

@ the stilt:

What where the scores of those test/benches?

Not from the same session but

3DMark FS = 1752
3DMark SD = 6580
3DMark11 = P3231
Cinebench R15 = 94 (ST) / 324 (MT)

Everything else at stock but MEMCLK at 2400MHz.

Tested on 15.3 WHQL drivers (internal) which give a slight boost for Godavari in 3DMark11.
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post #66 of 532 (permalink) Old 05-28-2015, 03:44 PM
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Thats not bad compared to what i got with this:

http://www.3dmark.com/fs/4610458

Would love to see how high it could go in firestrike and cinebench r15 when all is overclocked smile.gif

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post #67 of 532 (permalink) Old 05-28-2015, 03:52 PM
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Now would you? biggrin.gif

CPU: 4700MHz
CNB: 2200MHz
GNB: 1114MHz
MEMCLK: 2400MHz

3DMark Fire Strike
Score = 1992
Graphics Score = 2194
Physics Score = 5758
Combined Score = 747

3DMark Sky Diver
Score = 7613
Graphics Score = 7926
Physics Score = 6108
Combined Score = 8222

Cinebench R15
111 (ST) / 391 (MT)
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post #68 of 532 (permalink) Old 05-28-2015, 03:56 PM
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Hmm, I'm debating on whether or not to sell my 7850K and this up pick.

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post #69 of 532 (permalink) Old 05-28-2015, 03:59 PM - Thread Starter
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Quote:
Originally Posted by The Stilt View Post

Based my own tests on several different types of "Godavari silicon" the 7870K´s do indeed overclock better than Kaveri.
For the CPU part the average difference is around 300MHz, 200MHz for the CNB part and around 100MHz for the GPU.
The absolute clock ceiling for the CPU will be around the same (< 4800MHz) as it is process limited but Godavari will be able to do the same clocks as Kaveri with significantly less voltage.

The average clocks you can expect with a high-end motherboard and cooling are up to 4500 - 4700MHz for the CPU, 2100 - 2200MHz for CNB and 1040 - 1114MHz for the GPU. Compatible (Samsung or Hynix based) memory should run stable at 2400MHz without even touching the UNB voltage (CNB/GNB).

Both Kaveri and Godavari are extremely sensitive to fluctuations in CPU core voltage.
Since Godavari clocks higher than Kaveri it is even more sensitive to the fluctuations as the tolerance decreases at higher frequencies.
For that reason the load-line must be calibrated extremely accurately. At higher clocks you want the core voltage to stay within 15mV of the set-point even during the maximum loadstep. Both undershoot (droop) and overshoot hurt equally so simply maxing out the load-line control is not advised. Usually the -60% setting works the best.

Due the sensitivity to both voltage stability and other voltage characteristics the VRM plays a huge role when these parts are overclocked.
On a high-end motherboard with a digital VRM on it a chip might do 4.7GHz with just 1.45V. On a different lower-end motherboard the same chip might require 1.5V for 4.5GHz and be unable to reach any higher in otherwise identical conditions.

The CPU frequency usually reaches it´s peak at 1.45V - 1.475V depending on leakage.
It will accept higher voltage but usually the returns are non-existent. There is absolutely no point in trying to force the chip to do higher than xMHz if it requires more than 1.475V (actual).

The default voltages on 7870K´s are extremely high but also extremely conservative at the same time.
This means that there is a huge amount of undervolting potential in these chips. Not just for the CPU but for the UNB also.
On average the CPU requires around 200mV less voltage (abs. 1.2 - 1.25V) for the base frequency of 3.9GHz than the factory values indicate.
For the UNB the number is around 125mV (abs. 1.150V)

The power savings from undervolting are quite impressive.
The measurements are DCR (current over inductors) meaning they represent the actual power consumed by the APU.

Stock vs. Tuned voltages:

Pb0 (4100MHz) = 1.43750V vs. 1.1960V
P0 (3900MHz) = 1.38750V vs. 1.1530V
P1 (3800MHz) = 1.35000V vs. 1.1180V
P2 (3700MHz) = 1.30000V vs. 1.0960V
P3 (3500MHz) = 1.23750V vs. 1.0640V
P4 (3000MHz) = 1.08750V vs. 0.9630V
xx
xx

GNB (CNB + GNB) during 3D = 1.27500V vs. 1.0480V

Test: 3DMark11 Performance

Stock PMax VDD_CR DCR = 52.125W
Stock PMax VDDNB_CR DCR = 47.6875W
Total = 99.8125W

UV PMax VDD_CR DCR = 36.250W (-30.46%)
UV PMax VDDNB_CR DCR = 35.625W (-25.3%)
Total = 71.875W (-28%)

Test: 3DMark Sky Diver

Stock PMax VDD_CR DCR = 55.125W
Stock PMax VDDNB_CR DCR = 48.625W
Total = 103.75W

UV PMax VDD_CR DCR = 36.8125W (-33.21%)
UV PMax VDDNB_CR DCR = 37.1875W (-23.52%)
Total = 74.0W (-28.7%)

Test: 3DMark Fire Strike

Stock PMax VDD_CR DCR = 47.750W
Stock PMax VDDNB_CR DCR = 46.760W
Total = 94.51W

UV PMax VDD_CR DCR = 32.3125W (-32.33%)
UV PMax VDDNB_CR DCR = 35.000W (-25.15%)
Total = 67.3125W (-28.8%)

Test: Cinebench R15

Stock PMax VDD_CR DCR = 61.0625W

UV Pmax VDD_CR DCR = 35.6875W (-41.6%)




Many thanks for this post, which gives the best explanation I've ever seen of the overclocking potentials of any Apu.
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post #70 of 532 (permalink) Old 05-28-2015, 04:06 PM
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Quote:
Originally Posted by The Stilt View Post

Now would you? biggrin.gif

CPU: 4700MHz
CNB: 2200MHz
GNB: 1114MHz
MEMCLK: 2400MHz

3DMark Fire Strike
Score = 1992
Graphics Score = 2194
Physics Score = 5758
Combined Score = 747

3DMark Sky Diver
Score = 7613
Graphics Score = 7926
Physics Score = 6108
Combined Score = 8222

Cinebench R15
111 (ST) / 391 (MT)
I sold the AMD rig a few weeks ago, but i can give this:
http://www.3dmark.com/fs/4939354
My current rig big thinking of getting the 870k when it comes out and put it on an Asus pro board, you know just to have a bit of fun with it smile.gif
The physics score you got in firestrike are obut 10% higher than the 760k i benched and with 100mhz less speed, so thats not bad at all also the cinebench score is 20 higher than what i got with 760k, and again lower speed. Needless to say that i turned everything off that i could in taskmanager before i benched the 760k, so if you havent done that its even more empresive thumb.gif

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