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AMD Kaveri A10-7850K Overclock Guide - Page 131

post #1301 of 1334
Originally Posted by drmrlordx View Post

If you allow GeAPM throttling, you don't lose as many FPS as you'd expect since you don't spend 100% of the CPU's time throttled to p4 or p5 states. It's complicated. But basically if you do not use a solution like amdmsrtweaker, you can expect to lose a few frames here and there depending on your resolution. The more CPU-dependent the game, the more you lose. With my 7700k fully overclock to 4.7 GHz and all the trimmings (something I can't do anymore; chip is degraded), I could lose maybe 20-30 fps playing something old like TF2. On 3DMark FireStrike I would lose maybe 100-200 points. It was never that big of a deal.

The thing you need to think about, is that iGPU compute tasks (thing HSA/OpenCL 2.0/DirectX12) can also make the CPU throttle. If games ever mature to the point where they're using multiadapter tech that can incorporate the iGPU in some useful fashion, you will get CPU throttling even when using a dGPU. And that may have more of an impact.

Im sorry but my experience is quite the opposite. You do lose your boost clock on the CPU nearly 100% of the time. The 3.0 drop is a mandatory switch that kicks in whenever the iGPU us at or near full load.

As best i can tell the iGPU has 2 states it runs in. A low power state of 350MHz which allows the CPU to turbo and is usually what you deal with in your OS allowing for you to run your OC CPU stress tests and benches at full CPU clocks when doing mostly CPU heavy tests, and light gpu ones.

Then the iGPU has the stock 720mhz speed state which is what it runs during any sort of graphical load that is significant. That mode will always kick your CPU down to 3.0ghz no matter what else is going on temp or voltage or tdp wise.

That means that pretty much any video game worth its salt will downclock your CPU to the sub standard 3.0ghz clock, without the software fix enagaged of course, all the time. I find in any of the games or sythetics i have benched that it does indeed down clock the entire run because the boost clock on the iGPU is at the 720 state the entire run. Afterburner and 3Dmark both show this...with the only exception being during the physics/CPU tests in 3Dmark. It shows the iGPU down clocking to 350 with the CPU bumping back up to its higher P states and turbo states. Hence the higher scores on my above graphic for the faster CPU clocks. This will not happen however in most games, or at least ones i have tested. The boost clock on the gpu will cap out 100% of the time, which in turn drops your cpu to 3.0

I will double check when i get home tonight and can play with my Kaveri and post more pics to show what im talking about with some visual evidence. There may be situations or games where what you say is true, but i havnt tested them. (Minecraft? LoL)
Edited by gapottberg - 8/3/16 at 1:07pm
post #1302 of 1334
Originally Posted by gapottberg View Post

Im sorry but my experience is quite the opposite. You do lose your boost clock on the CPU nearly 100% of the time. The 3.0 drop is a mandatory switch that kicks in whenever the iGPU us at or near full load.

Ask The_Stilt, CPU monitoring programs will not detect the rapid switches between states. They just won't, ever. You are not going to be in p4/p5 permanently unless you're running Furmark.

Try locking your CPU @ 3 GHz and then run the same benchmark again at full clockspeeds with GeAPM throttling enabled and see what happens. You will get higher FPS despite the throttling and despite CPU-z and other programs telling you that you are throttled 100% of the time.
Then the iGPU has the stock 720mhz speed state which is what it runs during any sort of graphical load that is significant. That mode will always kick your CPU down to 3.0ghz no matter what else is going on temp or voltage or tdp wise.

Incorrect on the iGPU unless you are running stock settings. If you OC the iGPU it will run at whatever speed you tell it to run, assuming it's stable. I had mine at 1028 MHz for a very long time.
post #1303 of 1334
Ive read this thread like 4 times in its entirety. I know what Stilt says. I'm telling you i have evidence that says otherwise. It may be specific to my tests but none the less its there. I will post more data when i have time. Review the picture above for now and pay extra attention to the actual FPS and the CPU and iGPU clock speeds of each run.

I had similar experince in testing game data. I will will attempt to collect and post more here if i get to it before my sons Kaveri goes back to his moms.
post #1304 of 1334
Sorry, all I see are 3DMark scores with results that do not necessarily support the stated conclusion. You gain 300 points by letting the chip run @ 3.7 GHz with GeAPM throttling. 3DMark isn't all that sensitive to CPU speed so the gains are non-trivial. I would recommend something CPU-bound, like an older game run at a resolution where you can top 100 fps easily.

But hey believe what you will.
post #1305 of 1334
Sigh...you cant look at just the synthetic overall score and come to a valid conclusion. I tried to explain why looking at the individual tests and specificly the FPS matters, and what those differences infer in reguards how differring clocks on the gpu and cpu actually impact your FPS.

When i get home i will do a full anaylasis with graphics to explain my point of view. You can then take it or leave it. It matters not to me. I just want people to be better informed. Anacdotal evidence is a dime a dozen on here and many times its misleading or wrong. Data that can be replicated doesnt lie. Ill post my tet method and my scores and let the numbers do the talking.
post #1306 of 1334
Okay buddy.
post #1307 of 1334
[EDIT] Moved this post and the discussion it creates to another thread found here.

Analysis of Kaveri's Downclocking CPU to 3.0GHz when iGPU is under full load

It has long been known that without using a BIOS fix or other software manipulation that due to power constraints the Kaveri APU chips will force their CPU to down clock to 3.0GHz power state whenever the iGPU is under full load. It has often been speculated what the exact impact of this is on gaming performance. That speculation has lead to a couple of commonly held beliefs based on anecdotal evidence. They are as follows...

#1: The bandwidth bottleneck on the GPU is so large that lower CPU clocks will show little to no performance difference even if they were able to go higher than 3.0GHz.

#2: The clock speeds reported in monitoring software are inaccurate and while they show CPU clocks being held at 3.0GHz, they often jump intermittently between higher states and 3.0GHz depending on the iGPU load. This will allow much of the performance loss one would expect during gaming at lower CPU clocks to be nominal.

My testing will deal primarily with the second Hypothesis. In theory, if that statement is true, then with all other things being relatively equal we should see real performance gains over two tests where the only difference is CPU clock. Being locked at 3.0GHz or being able to periodically able to go higher during the test (even if software doesn't pick it up) would be the deciding factor.

For example, a CPU locked at 3.0GHz in BIOS during a test would exhibit less performance than one that was locked at 3.7GHz in the BIOS, and down clocks to 3.0GHz sporadically during the test due to iGPU loads being high. Because it still maintains higher clocks at times during the run, its scores should show that benefit.

However, should the 3.0GHz downclock actually be persistent and software is reporting properly measured downclocks of 3.0GHz during heavy iGPU loads accurately, (which contradicts speculation #2) then we should see near identical performance between a test with higher CPU clocks and one with CPU locked at 3.0GHz in BIOS.

Additionally, if the 3.0GHz cap is indeed persistent (and you choose not to use a software or BIOS fix) then you may find the fastest performance by locking the CPU at 3.0GHz (with possibly an undervolt to lower temps allowing more headroom on iGPU), and pushing your iGPU clock as high as possible.

NOTE: This lower CPU clock will nominally reduce performance during non iGPU heavy loads, but it will not have in impact during any gaming or other iGPU heavy workloads.

My testing method for this as well as my Hardware set up is as follows...

Using 3DMark do 4 runs of their Skydiver Bench Test, with each run having different Clock speeds on the CPU/GPU as follows.

CPU 3.0 / iGPU 720
CPU 3.7 / iGPU 720

CPU 3.0 / iGPU 1029
CPU 3.7 / iGPU 1029

Looking only at the tests that maximize iGPU load we will record the FPS scores for GFX test 1 and 2 and the Combined Test. The Overall score and Physics tests will be left out due to the fact that they do not put the iGPU under full load. This allows the CPU to maintain higher clocks. We are not investigating whether the CPU can maintain higher clocks under light iGPU loads such as the physics test or your OS home screen. We know it can. We only want to test it when the iGPU is under full load like it would be in any video game with demanding graphics. This type of heavy iGPU load only happens in GFX test 1, 2 and the combined test.

My Hardware list and setting is as follows:

Kaveri 7850K Variable clocks on CPU and iGPU as listed above
8GB Gskill Trident X @ 2133MHz C9.
MSI A88XM Gaming NB @1800

Final commentary...

If the tests shows significant performance gains with higher CPU clocks we can support speculation point #2 citing our test a evidence. If it does not, then we as a community should do further investigation into the matter and consider rejecting it.

The Results: proof.gif
Warning: Spoiler! (Click to show)

I will let the community decide for themselves what this means. I have done my part and will not have access to this rig for a long time after today as it goes home with my son today. Hope this was helpful. thumb.gif
Edited by gapottberg - 8/5/16 at 4:26pm
post #1308 of 1334
I don't think it is a 3000Mhz limit. I think it is a 1000Mhz drop (going from memory here though).

I really think the APU was way too aggressive in trying to restrict the chip's TDP by dropping the CPU's speed. I always used MSRTweaker to adjust the power states, so that if it did drop, I had set what it dropped to (I.e. I just set those lower power states to be my overclocked multiplier and voltage).

Also... unless you are running a CPU intensive program/game, then you are unlikely to notice that much difference. If playing something like Planetside 2, or a RTS, then you are going to see a big impact from the CPU speed dropping, and that is not reflected in your test.

My own chip:

I have been considering getting a better CPU for this system, as mine only goes to around 4.3Ghz reliably, but even if I got 4.7 from an 880k or 7890k or something, I just don't think it would be worth it. I'd be better getting a new motherboard/cpu etc.

As for overclocking, I have to admit I really don't know what voltage settings I should be tinkering with on this 7850K. If I run a 44 multiplier.. it will just randomly freeze the PC, even on desktop. i can go for 30 mins.. and then it just freeze. It is very weird.
Edited by Scougar - 8/9/16 at 5:46am
post #1309 of 1334
Hello guys, nice forum you have here smile.gif

Anyway I would like to ask some questions because I can see some experienced guys here, i'm a bit of a noob for OC... anyway here it goes.

I have obviously A10 7850K Apu with GA-F2A88X-D3H Gigabyte MB and 2x4 GB of Kingston HyperX and the cpu is cooled by Cooler Master Nepton 120XL. I put the PC together several years ago just as a second computer mainly for work and to play some casual games. I've played most GPU intensive games on my Asus Rog G750jz notebook. But several days ago i've bought RX470 Nitro+ 8GB (couldn't resist the price in my country smile.gif ) and obviously the cpu is a bottleneck, anyway until I put some money aside for a new mb, cpu and ram I've done the following to loosen up the bootleneck a bit.

I've disabled the igpu, and OC'd the 7850k.. But for starters the default V of the cpu was 1.45 to begin with xD .. I can't get any stable OC past 4.4 and that is with 1.49 Vcore and it to be stable at that I had to enable the LCC to medium. When I monitor it with Aida or HW monitor the core power varies from 1.50-1.52. It's high but am I missing something? If i don't use the iGpu should i raise the voltage to the NB also? I'm a bit confused, as I say i'm a beginner. The same thing happens either when i overclock in the Bios or with Amd Overdrive. Also when i do a auto system tuning in Overdrive with the stock voltage it always crashes at 4.4.

Any feedback would be greatly appriciated. Thank You
post #1310 of 1334

I'm not sure what the phase spec of your motherboard is but I think it should be described as low to moderate, anyway, it's obviously not something Gigabyte want to advertise. So for that level of VRM control support, and with only the one small heatsink over them, 4.4Ghz stable for a 7850K is respectable. I don't think you need worry too much about anything below 1.55V as long as you keep the temperature well below 80C or don't stay up there for days on end.

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