Processor for ROCK (8th generation)

i am looking to choose a currently available intel core processor that will perform at or better than the specs listed on the roon optimized core kit knowledge base page for ROCK For Large Libraries or DSP Use.

my use case is dsd512 upsampling via roon dsp, one zone – fanless chassis, M.2 NVMe boot and data drives, motherboard with intel 370 chipset.

the roon recommended NUC-7i7BNH has the intel core i7-7567U processor which has the following performance specs…

  • cores / threads : 2 / 4
  • processor base frequency : 3.5GHz
  • processor max frequency : 4.0GHZ
  • cache : 4MB
  • bus speed : 4 GT/s OPI
  • TDP : 28W

several questions to help guide the selection of a processor…

  1. which are the determining processor performance specs for my use case that need to be met or exceed.

  2. in addition to ROCK, would the same specs hold true if running roon core or roon server on a headless PC?

  3. how important is keeping the TDP low (the newer generation processors have 35W, 65W and 95W TDPs), especially given the fanless chassis?


For all DSP usage in Roon, single core performance is king. While there is a tickbox to do some multithreading in the DSP engine, that only applies to subfeatures (like upsampling). So you want to favor a CPU part with maximum single core sustained and turbo performance over massively multi-core part with lower single core performance. Especially doing DSD512 upsampling, which will basically consume an entire core alone on a Kaby Lake-based i7 optimized for single-core peformance.

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What I use (on a H310) vs the 7567U.

thanks - extremely helpful !

does the TDP matter? for a fanless chassis, is there a general TDP spec not to exceed? many current generation CPUs that max single core base and turbo frequency have a 65W or 95W TDP.

thanks! 3.5GHz base freq – assuming 65W TDP is not an issue, that may be a good choice.

are you using a fanless chassis?

Don’t know where you intend to have this machine, but if it’s a different room than your listening post (as Roon recommends) then whether it has a fan or not is not important.

As a matter of fact, there is a greater danger of overheating without a fan. However, with TDP of 28 watts that’s probably won’t a problem.

BTW - If you want a 9th gen chip, you’ll have to wait awhile. :slightly_smiling_face:

TDP doesn’t matter because a fanless chassis also doesn’t matter because you should have the system in a different room from your listening environment anyway, connected to an playback endpoint via Ethernet.

TDP is not relevant, other than to what you are willing to pay in Electricity to run your system. Technically speaking, fanless cases can be (and have been!) designed for any TDP. But they are often very expensive and not worth it. Especially since you shouldn’t have the Roon Core in your listening environment, anyway…

More powerful CPUs will have a higher TDP. Considering you want to upsample to DSD512, worrying about low power should be the last of your concerns, considering how much compute is required to perform said upsampling.

@aKnyght It is in a silent chassis and sits in a communal area of our home.

Ultimately, not really. All modern CPUs have multiple internal temperature sensors and an internal “governor”. They won’t overheat so much as start to thermal throttle themselves to keep from exceeding their max limit. End result is the CPU runs much slower. Like most Apple Mac Hardware…


device will be on the audio rack – for the purposes of optical-isolation and, thereby, removal of all upstream electrical noise, the device will connect to the network via wi-fi and then directly to the USB DAC. i have had spectacular results with this topology in my current set-up.

could move the device into another room when / if i install a fiber network connection to the audio rack, but would then have to get a FMC + the associated cables and power supply… so, not sure i really gain anything.

keeping my eyes open for a suitable DAC with an SFP port to accept a fiber input. but i think it will be a while before they are readily available.

just heard back from the chassis manufacturer re: TDP…

“Our test shows high TDP CPU does not run hotter doing the same task especially when their clock speed is the same.”

…makes sense.

Yes, it very much does.

Cases are designed to dissipate a certain amount of heat - i.e, for a given max TDP, that’s why some Akasas don’t officially support i7 NUCs. Your environment (no AC in the summer…) matters as well. Bigger cases, with bigger heatsinks, dissipate more heat - it’s physics. Stick to what the case’s manufacturer recommends, within reason of course - don’t stick a 95 watter inside a case specced for 65w, but don’t sweat it too, too much if you’re putting a 75 watt CPU inside it, and you’ve got your AC set to “Russian winter” type of thing. You’re not running prime95, 24/7.

thanks for all the help and information!!

in looking at the processors currently available for the h370 chipset, there are several i5 and i3 processors that have a higher base frequency than the i7-7567U processor in the roon specified i7 NUC.

i7-7567U… 3.5GHz (4.0GHz max) / 2 core, 4 threads / 28W TDP

i5-8600K… 3.6GHz (4.3GHz max) / 6 core, 6 threads / 95W TDP
i3-8350K… 4.0GHz (4.0GHz max) / 4 core, 4 threads / 91W TDP

the i3-8350K would seem to meet the requirements implied by the roon specified i7 NUC processor for large libraries and DSP use… and it costs quite a bit less.

any comments / thoughts / recommendations here regarding the i3 or i5 suitability for my use case in the OP would be very welcome!

one additional detail - my library is pretty small: cannot imagine it ever exceeding 2,500 albums.

also, i am confident the higher TDPs are not an issue in a well designed fanless chassis, particularly given:

  1. intel defines TDP as: “…the average power, in watts, the processor dissipates when operating at Base Frequency with all cores active under an Intel-defined, high-complexity workload.”

  2. roon DSP, including upsampling, is not parallelized and runs on one core (correct me if i am wrong on this point).

Neither of the “K” processors meet ROCK requirements, because they’re not in NUCs :wink:

If you want something that’s officially supported, pick up one of the recommended NUCs, slap it into an Akasa case, add a fast NVMe drive for the database and a suitable data drive, done. Here’s a side-by-side that includes single core speeds.

If you’re going to go the not-officially-supported MOCK route, an i3 should do the trick. Here’s that comparison with the recommended i7 NUC. There are several fanless case options there, depending on your design sensibilities, dexterity with a screwdriver, and desired level of finishing.

At the end of the day, it depends on your priorities: you’re going to have to pick two out of “faster, cheaper, officially supported”, and that’s a choice no one else can make for you.

If you want to achieve optical isolation but place the ROCK in another room, you might want to check out one of the opticalRendu/opticalModule solutions here

Yes. Visit the Akasa web site and check out the fanless NUC compatibility list and you’ll see they only support fairly low TDP CPU. With a higher TDP CPU it gets really difficult and expensive to make a proper fanless case.

There were overheating cases with both fan and fanless chassis for NUC7i7BNH 28W TDP. Although not intuitive, this TDP figure can be exceeded in practice. This review measured it at 58.5W:

Also check out this thread:

And this good example:

My advice is to forget about arbitrary high power CPU and use only a NUC that’s proven by other members in this forum.

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It uses two threads (cores) per zone if you enable Parallelize Sigma Delta Modulator. Other threads are still needed for other tasks like analysis, UI and library management, etc. So all cores can be used.

peter – as always, thanks very much for the help!

i would use a NUC except that my specs call for a mini-ITX motherboard having a PCIe expansion slot (h370 or h310 chipset). so now, i am just trying to find the CPU with the best performance in terms of single-zone DSD upsampling that will not exceed the thermal management capabilities of the case.

i am using an HDPlex H3 V2 case which has a more robust heatsink system than that of the akasa and can, hopefully, accommodate a somewhat higher TDP CPU.

one other CPU that might possibly work is:

  • i3-8300T… 3.2GHz (3.2GHz max) / 4 core, 4 threads / 35W TDP

or even:

  • i7-8700T… 2.4GHz (4.0GHz max) / 6 core, 12 threads / 35W TDP
  • i5-8600T… 2.3GHz (3.7GHz max) / 6 core, 6 threads / 35W TDP

however, their base speeds might be too low for dsd512 upsampling? if so, i could always turn on multi-threading and/or just live with dsd256 or even dsd128 upsampling.

any thoughts the “T” CPUs, especially the i3, would be great.

i would go with a i5-8400 or i5-9400. Why? Basically these cpus use all the same power in idle.
And the i5-8400 and the 9400 are very comode in power use when under heavy load. But have high enough base clock speeds and cores. Have a look here. sorry it is german but the table should be readable. Tey use a 1080ti but the results are all comparable.
Right now i have to make the same decision as you.
Buy a nuc or build my own rig? I tend to go with a Asrock deskmini 310 and a 8400 cpu. Should be arround 12w idle and when asking for more power it is ready. and when it is not in heavy use these cpus wont consume more then the Tmodels.
One more thing you should think about. Cpus with more power/clockspeed tend to do the same work in less time. So they can go to lower power states earlier. Or they do it with less clockspeed.
And when they get too hot, they throttel down. And wheter you use a 35w or a 65w modell. the temp limits are the same. When the cooling system can handle it it makes absolutely no sence to use a T-Model.