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Question Maybe I found a serious bug in Cinebench R20???

marcUK2

Member
Sep 23, 2019
42
32
51
Hi,

Just got myself a 3950x and thought I would do some overclocking/underclocking...For a minute I thought I was going mad, but then I realized this might be a big bug, so perhaps someone else can verify?

Everything is stock at the moment, using Ryzen Master I activated the creator mode, but changed nothing, Cinebench R20 gives me a score of ~9000

Power is ~140W, each core using around ~7W, with the rest going to the IO Die I assume. The all core speed during CB20 is about 3950Mhz

Now, If I go to Profile1, which is in a default state, but click on PBO, and set PPT, TDC, and EDC to their minumum values, 71,47,70....
Power is no down to ~70W, cores at ~3W, and the all core speed is barely over 2100Mhz..

But CB20 gives me repeated scores in this configuration of ~8500.

Which surly cannot be correct.

I timed the runs. In creator mode it is 37s, and in the custom low power mode it is 58s..

Can anyone replicate this??
 

DrMrLordX

Lifer
Apr 27, 2000
16,371
5,281
136
I don't have a 3950x, but I'm not sure why you think there is a bug. That all-core speed is not correct. Matisse is much more efficient at slightly lower clocks and voltages. You have merely discovered that fact.
 

marcUK2

Member
Sep 23, 2019
42
32
51
I don't have a 3950x, but I'm not sure why you think there is a bug. That all-core speed is not correct. Matisse is much more efficient at slightly lower clocks and voltages. You have merely discovered that fact.
Yes, but you dont score 9000 when running all core at 3.95Ghz and then score 8500 when running all core at 2.1Ghz
 

DrMrLordX

Lifer
Apr 27, 2000
16,371
5,281
136
As reported by RyzenMaster, CPUZ, and CPUID HWMonitor....and the actual time CB takes to complete goes from 37 seconds to 58s.....I dont think so
Hmm. There's no way your CPU should be running at that speed with those power settings though.

edit: I tried your PBO settings via Ryzen Master on my 3900x. The total render time (not counting prep time before the render) was ~47s, with a steady clockspeed of 3500 MHz. There's no way your 3950x should be slower than my 3900x with identical PBO settings.
 
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Topweasel

Diamond Member
Oct 19, 2000
5,327
1,525
136
Any chance you can take a snapshot of RM with the CPU speed graph enabled and the CB20 run. Something seems really weird.
 

marcUK2

Member
Sep 23, 2019
42
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3950x2.PNG3950x3.PNG

Im thinking Ive just been unlucky in the silicon lottery. Yes the chip runs to spec pretty much, but draws a lot of power. My 3700x runs all core at 4.25ghz at 1.325V permanently on this MB with the stock AMD cooler.
 

marcUK2

Member
Sep 23, 2019
42
32
51
Defaults are 142,95,140..and this gets me ~9000 in CB20 at less than 75C under many runs,....which is plenty good enough and within margin of stock operation. I will leave it here. This is just a poor chip/mb combo, but within spec.
 

Hitman928

Platinum Member
Apr 15, 2012
2,774
2,125
136
I don't use Ryzen Master, is there any reason to have Creator Mode turned on with a 3950x? Does PBO need to be on? Do you have a HPET toggle on the board?
 

Hitman928

Platinum Member
Apr 15, 2012
2,774
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On the 3950x it enables both Chiplets. The game mode disables a CCD and it becomes an 8 core chip. I cant see any other differences.
Ok, I didn't realize it was active for a 3950x since they made it really just for the 2nd gen (Zen+) Threadrippers.
 

marcUK2

Member
Sep 23, 2019
42
32
51
Whats up with those ram timings ?
You can gain more performance by adjusting your memory setup (in other programs then cinebench)
Ive got 16gb of 3000mhz memory, and 32gb of 3200mhz memory, so I run the memory clock and fabric at 1:1, at the 1500mhz rate. Is that correct?
 

Hitman928

Platinum Member
Apr 15, 2012
2,774
2,125
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Ive got 16gb of 3000mhz memory, and 32gb of 3200mhz memory, so I run the memory clock and fabric at 1:1, at the 1500mhz rate. Is that correct?
He was talking about your timings (CAS latency, etc.) which are very poor for running at 1500 MHz rate. With that said, mixing memory modules is usually a bad idea because their subtimings can be wildly different.

In Ryzen Master, can you turn PBO off but leave the lowered power limits on?
 

marcUK2

Member
Sep 23, 2019
42
32
51
He was talking about your timings (CAS latency, etc.) which are very poor for running at 1500 MHz rate. With that said, mixing memory modules is usually a bad idea because their subtimings can be wildly different.

In Ryzen Master, can you turn PBO off but leave the lowered power limits on?
I dont know enough to mess with that, what kind of performance loss am I getting?
I need stability greater than anything because I do alot of work on this PC.

In Ryzen Master, I tried what you suggested, but I dont think its possible in any mode on offer.
I can set lower limits with PBO on, but actually, Im having difficulty turning PBO off even from the BIOS - it still boosts to 4.65 no matter what I set.

I can ofcourse do complete manual and set all core to 4GHZ at 1.2V, but then I get no boost at all, my CB goes up by 300 points, but then I lose a bit on SingleThread....

would be nice if in RM, I could set 4GHZ all core, but still have boost to 4.4GHZ when conditions allowed, but this does not seem possible.
 

Det0x

Senior member
Sep 11, 2014
378
272
136
Ive got 16gb of 3000mhz memory, and 32gb of 3200mhz memory, so I run the memory clock and fabric at 1:1, at the 1500mhz rate. Is that correct?
Ah that explains alot, generally its a bad idea to run a asymmetrical memory setup.

If you want a better explanation why its bad, you can watch this video with goes alittle into why its not recommend:
Just replace the imagined 4+8gigs with your 8+16gigs.

I would remove the 16gigs set and only use the 32gigs set with XMP enabled as your current memory timings is not ideal.
(you could make everything work fine/ok in a asymmetrical memory setup, but then you need to tweak everything by hand which require lots of time)

Your current primary memory timings is 22-21-21-71 @ 3000MT/s, compared to my (24/7) settings which is 14-11-12-36 @ 3660MT/s. My other settings and CB20 score can be found here (Note: please do not try to just copy my memory settings as they are fine tuned to my specific memory kit)
 
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Hitman928

Platinum Member
Apr 15, 2012
2,774
2,125
136
I dont know enough to mess with that, what kind of performance loss am I getting?
I need stability greater than anything because I do alot of work on this PC.

In Ryzen Master, I tried what you suggested, but I dont think its possible in any mode on offer.
I can set lower limits with PBO on, but actually, Im having difficulty turning PBO off even from the BIOS - it still boosts to 4.65 no matter what I set.

I can ofcourse do complete manual and set all core to 4GHZ at 1.2V, but then I get no boost at all, my CB goes up by 300 points, but then I lose a bit on SingleThread....

would be nice if in RM, I could set 4GHZ all core, but still have boost to 4.4GHZ when conditions allowed, but this does not seem possible.
I'm just curious if PBO is causing the lower than expected frequency when lowering the power limits. I know it sounds counter-intuitive and it may not be happening, but PBO allows for voltages and power limits to exceed the default limits. You are then manually lowering those limits, so those settings might be fighting each other, so to speak.

Although, looking at some of the 4800HS results, it looks like you might be pretty inline with the expected frequencies for 16 cores at ~70W.
 

marcUK2

Member
Sep 23, 2019
42
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So I decided to enable the XMP 3200 profile for my memory, which gives me
xmp.PNG
Im not fiddling with timings, because I dont really know what they do, and I dont really have time myself.
However my CB20 score did not improve at all, but the system seems OK, so I will leave it as is.

Incidently, disabling all the crap that loads at startup (GFExperience, AutoDesk Utility, UE Launcher etc...) gives me an extra 150-200CB, so I am well into the high 9000's now, so I assume that this is as good as its going to get with this MB combo. Its a considerable step up from my 3700X.

I will try to pick up another 2x16GB kit when I see my set on offer, but I cant quite get by on 32GB at the moment
 
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