1 Topic by ramses (edited by ramses 2018-07-20 06:54:22)

  • ramses
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Topic: Does somebody have an AMD 1950X (threadripper) based system ?

In an Anandtech system performance review I found on the last page the following statement in regards to DPC latency.

https://www.anandtech.com/show/13081/th … d-review/7

Every motherboard for the Ryzen Threadripper that we have tested to this date has a relatively high DPC latency. The ASUS X399 ROG Zenith Extreme has a DPC latency of 246 μs, which may seem high to some enthusiasts, yet it is the best that we have seen to this date and by a significant margin.

If somebody has a Threadripper 1950X based system I would be very interested to compare DPC latencies under Win7 and Win10 on a system tuned for audio.

You can contact me via e-mail (forum link). Many thanks.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14

2 Reply by Timur Born (edited by Timur Born 2018-07-20 07:35:49)

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Re: Does somebody have an AMD 1950X (threadripper) based system ?

Unfortunately I only have a 1800X based Ryzen system. But 246 μs is not a problem anyway and Anandtech does not clarify if that is the maximum or average value and what power profile and BIOS (C-states) settings where used. Look at this example:

Highest measured interrupt to DPC latency (µs):       354,514229
Average measured interrupt to DPC latency (µs):       2,480283

Quite the difference. And 354 µs maximum still is not a problem even at lowest buffer settings.

3 Reply by ramses (edited by ramses 2018-07-20 07:55:11)

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Re: Does somebody have an AMD 1950X (threadripper) based system ?

Timur Born wrote:

And 354 µs maximum still is not a problem even at lowest buffer settings.

True.

On the other hand, the lower this DPC latency value is, the more likely it is, that you can run higher audio workloads with smaller ASIO buffersizes, as the CPU can react more agile on incoming and outgoing audio.

Maybe not necessary if you simply record many channels but have relatively few VST's and no VSTi's in use.

But if you record with a some VSTis and maybe also play a virtual amp (running in the DAW) and
need to use an ASIO buffersize of 128 or below, then this might become critical.

For me as guitarist an ASIO buffersize of 128 is fine, when I play such a virtual amp (VSTi).
But I heard of a drummer in a forum who claims to require even less for his drumkit.

In such situations where you are "bound" to use ASIO buffersizes in the range of 32 - 128, then it is very useful or even necessary to fine tune the system for more agility.

So I prefer to see DPC latencies under 50us down to 1-20us on average on an idle system.
Especially useful if you record using VSTi's and VSTs that produce higher CPU loads.

But I agree with you, if its not required then there is no reason to be worried about this.
It always depends on the type of system load and how you are recording / monitoring.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14
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Re: Does somebody have an AMD 1950X (threadripper) based system ?

Suggest that you bring this question to Pete Kaine (Scan Pro Audio) on Gearslutz form, Music Computer subforum, the "today we build our studio pc" sticky thread.  Note that it is a long thread with long history and a large number of posts, so you might want to skip the first 7 or so years of it.
https://www.gearslutz.com/board/music-c … hread.html

Here is a link to a subset of his blog postings tagged, "DAWBench".
http://www.scanproaudio.info/tag/dawbench/

and this one...
http://www.scanproaudio.info/2017/08/14 … 20x-1950x/

5 Reply by ramses (edited by ramses 2018-09-07 07:59:10)

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Re: Does somebody have an AMD 1950X (threadripper) based system ?

Many thanks this validates my suspicion that for recording and mixing - with a few VSTi 's active - and at lower ASIO buffer sizes  Intel CPUs with higher IPC, clock speeds over ~3.5 GHz and more simple memory architecture are still preferrable. Also interesting the comment about CPU war and the phase of optimization of new CPUs in terms of heat.

I think I did everything right with my selection of E5-1650v3. Sadly I was 1y too early as E5-1650v4 brought definitely an improvement in terms of lower heat.

Sadly not in terms of running AVX instructions. Although the v4 CPU ran 200 MHZ quicker in general in Cubase it had to fallback to the same 3.5 GHZ for cores running AVX instructions as the V3 CPU.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14