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Re: Suggestions for new PC

Postby Agharta » Sun Feb 25, 2018 1:37 am

job wrote:He is the 7900x at full load with all cores locked to 3.3GHz (which is bare bones stock), whilst honouring each cores requested VID value.

Image


The plot thickens! :o
What software is showing that info?

As part of Intel's Turbo Boost Max 3.0 they rate each core and the top two get preferred status which can lead to higher boost speeds for loads that require up to 2 cores.
So as part of that it makes sense that they rate each core with its own voltage.
But I still haven't seen any hard evidence that they will run all cores at individual voltages at full load.
No offence, but a cropped image of an unknown utility is not evidence as I've seen so much bogus info reported by such tools.
But Intel did bring the VRM back on to the chip for SkyLake X so maybe that is how they have managed to add up to 18 individual voltage planes just for the cores.
If you are correct then kudos to you as I have not seen this mentioned in any reviews which is a surprise considering what a big change it is.
The current 8th generation Coffee Lake chips don't support individual core voltages but Intel may have felt the need to add this to the server chips.
We will see... :wave:
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Re: Suggestions for new PC

Postby ef37a » Sun Feb 25, 2018 8:58 am

I LOVE this!
I am only understanding about every tenth word/concept but it is always fascinating to read people who really know what they are talking about.

Dave.
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Re: Suggestions for new PC

Postby job » Sun Feb 25, 2018 12:36 pm

It's HWinfo.

It might help to remember what these terms are. VID is a table of voltages, and we can view it as 'the voltage that my cores request and use straight out of the box if i don't touch anything'. Vcore is the current voltage being sent through the CPU, and is quite often displayed by way of taking Vccin and dividing by 2, although not always.

Displayed VID value comes from a CPU sensor, it's read from the pins and is what the cores request and use when left to their own devices. Vcore is a motherboard sensor (or user implemented), and is the voltage that's currently going through the CPU.

If we change Vcore, then that particular voltage that we set becomes a target to achieve. In the screenshot above i haven't done any of this, i've lock all cores to 3.3GHz and then allowed the CPU to do whatever it wants to do electrically. Therefore, the cores are using VID values.
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Re: Suggestions for new PC

Postby mozart999uk » Mon Feb 26, 2018 10:39 am

melciados wrote:
mozart999uk wrote:So rather a generic question I know but......

I'm currently running a 5 year old scan 3xs PC. i7 3930k. Overclocked at 4.2gHz. 64 GB ram.


Man, you have a awesome workstation! I wish i could get this. What is the price of your setup today?

I'm afraid I don't know. The 3930 is quite an old chip so I'm not sure where you would get a workstation built with it in.....sorry
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Re: Suggestions for new PC

Postby Pete Kaine » Tue Feb 27, 2018 3:51 pm

Agharta wrote:I noticed years ago that some motherboards were over-volting the CPU even if you didn't manually over overclock.

This was Asus or Gigabyte and you had to manually change a BIOS setting from Auto to Stock or some such.

Yeah, frequently annoying. A lot of the time you can still drop various voltages at stock, shave off 10 degrees and still pass a 24-hour burn test. Talk about them playing it safe with the factory settings.

Also for a period, those same firms used to boost the default buss clock ratio to 103:100 for no real reason, other than it put them a fraction ahead of other firms in various mag benchmarks. The number of early PCIe cards it used to trip up was painful for a time given they didn't give any real warning of this anywhere.

I noticed that AVX512 can process 32-bit data types so in theory it could be used to accelerate audio tasks.
I am not clear what type of operations it works with though so do you know if it handles those that are relevant to a DAW?

Afraid not, my knowledge of that is a little scant.

After seeing AVX testing cook my desk during the initial round of testing, I really wanted to know if running real-time code would hammer the rig in the same fashion as the synthetics. I made contact with Melda over it who have always noted that they use the extra instruction sets where performance can be leveraged and tried to suss out with them if anything in the real world was likely to hit that sort of level.

The conclusion was that the code runs in bursts as and when it's needed, so no, at this point heavy continuous use of it wasn't really something we'd see in the audio field, at least in the short term and that it shouldn't be a concern outside of those synthetics.

So far that has proven true, although that's not to say it won't change in the future and of course if anyone knows of a package out there that will take advantage of it in a more demanding fashion, I'm all for giving it another thrashing!

job wrote:For example, the requested Vcore on one of my 7900x's cores under turbo boost was 1.37V. However, it can run 4.5GHz at 1.15V and 4.8GHz at 1.25V, which is currently where it's at with adaptive voltage. So it's running at a higher speed and at a lower voltage than it would be if the user wasn't in charge.

As for motherboards auto-overclocking the hardware as some kind of feature, I would agree that the default setting should be off, not on.

Can't agree enough with the auto overclocking needing to be off at default. You've also nailed the Vcore voltages that tripped me up initially. As you say, when you run the voltage measurements at stock and see 1.35v, you really don't tend to expect it to be running stable at 1.15v after clocking it upwards!

mozart999uk wrote:Thanks Pete. Really interesting. All sounds good. Can I get in touch with you via email when I'm ready to order ...to thrash out the spec?

Sure, my mail hasn't changed if we exchanged them last time, otherwise, nudge me over PM and I'll update you with my latest when the time comes.

Agharta wrote:I like to see under-volting but there isn’t the interest in it that is seen with over-clocking so you rarely see it in reviews.
There is one way to sometimes get a sense of how well a chip might under-volt by looking at how it over-clocks.
Some chips are binned very aggressively meaning that they ship with very little headroom for over-clocking.

To be fair thats pretty much covered by the "S" and "T" editions of the chips to some degree as those tend to offer lower voltage editions of popular chips.

7700K = 91w
7700 = 65w
7700T = 35w

You could grab the "k" and undervolt, but then the "T" edition is normally cheaper anyway.
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Re: Suggestions for new PC

Postby mozart999uk » Tue Feb 27, 2018 4:00 pm

Pete Kaine wrote:[

mozart999uk wrote:Thanks Pete. Really interesting. All sounds good. Can I get in touch with you via email when I'm ready to order ...to thrash out the spec?

Sure, my mail hasn't changed if we exchanged them last time, otherwise, nudge me over PM and I'll update you with my latest when the time comes.


Thanks. Don't think we've ever exchanged emails so I'll pop you over a PM
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Re: Suggestions for new PC

Postby Agharta » Sat Mar 03, 2018 2:02 pm

Pete Kaine wrote:To be fair thats pretty much covered by the "S" and "T" editions of the chips to some degree as those tend to offer lower voltage editions of popular chips.

7700K = 91w
7700 = 65w
7700T = 35w

You could grab the "k" and undervolt, but then the "T" edition is normally cheaper anyway.

You buy the K version because you want the higher performance so the 35W chips aren't going to cut it.
So by under-volting you make it easier to cool the CPU silently which shouldn't be that hard for a chip rated at 95W such as the i7-8700K.

I think under-volting is more critical when using the 125W CPUs and you can always drop the clock a bit as well as under-volting.
Wider and slower is usually the way to go for power efficiency which is what counts with quiet computing unless you must have the highest clock speed which some prefer.
So a 10 or 12 core under-volted, maybe with the speed reduced by a few hundred mega-thingies might be optimal. I haven't seen any data on these Sky Lake X chips under-volted.
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Re: Suggestions for new PC

Postby wireman » Sun Mar 04, 2018 1:40 pm

My PC is 6 years old (Windows7/64,i5-2500k,16GB RAM) and has been rock solid. I would have replaced it by now but unfortunately Windows 10 is a problem for me. I find it completely unacceptable for an OS to install updates automatically and so far have not been prepared to invest the time in working out how to prevent this. There are many times in the past few years where being able to choose not to install or delay an update because they were unwanted (Windows 10 nag updates etc.) or broken has been important to me. I don't want to take the risk that something breaks without me being aware of the exact changes that could be involved.

I'm also aware that I have to take steps to disable W10 telemetry.

And I have an ECHO Audiofire, so would have to replace that.
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Re: Suggestions for new PC

Postby Pete Kaine » Mon Mar 05, 2018 5:56 pm

Agharta wrote:You buy the K version because you want the higher performance so the 35W chips aren't going to cut it.

Well, yes, but the current chips are pretty close together performance wise and if you underclock, well, you won't get much savings, at least on the current chips.

8700k = 95w+ = 16127
8700 = 65w+ = 15200

The last score is CPU benchmark average, we're looking at about 7% between them for that 35w difference. If you talk about underclocking the 8700K and dropping a 100mhz here and there, you're going to be seeing the same performance very quickly without experiencing any other real gains.

Chances are the's a bigger difference between the 8700T and standard, but I've still not seen one of those physically at this point, and benchmarks are otherwise sparse.

[/quote]
So by under-volting you make it easier to cool the CPU silently which shouldn't be that hard for a chip rated at 95W such as the i7-8700K.
[/quote]

Silently? I can count on one hand the number of passive coolers left out there and on 2 fingers the number that can cool over 85w.

The best commercial (ruling out the crazy french custom solutions) one I'm aware of is the nofan 95 and that does 95 degrees. The problem is that the K when it turbos the cores goes above a 95w pull. Sure, you can undervolt and put it to a locked 8700, but then you might as well save the money and just buy a 8700 and go with the 65w edition to give you more headroom.

I think under-volting is more critical when using the 125W CPUs and you can always drop the clock a bit as well as under-volting.

Or you can fit a cooler that's rated to 220W and run it at half speed.

Wider and slower is usually the way to go for power efficiency which is what counts with quiet computing unless you must have the highest clock speed which some prefer.
So a 10 or 12 core under-volted, maybe with the speed reduced by a few hundred mega-thingies might be optimal. I haven't seen any data on these Sky Lake X chips under-volted.

It's not to say I don't agree with some of what you're saying, I just don't think it get's you the benefit in the mid-range anymore, not when you can just save money and buy the cheaper, lower power model and still get 95% of the performance of the upper model with none of the cooling concerns or having to piss about getting it stable.

On the other hand, I'd agree with the i9's and more enthusiast models where the power ramp-up is around 20% under load. Scaling that back certainly has the pro's you've already listed.
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