How to build your own iMac Pro [Successful Build/Extended Guide]

[kgp]

For those with a Gigabyte X299 boards (I have a Designare EX), here are my BIOS settings (and EFI folder) to get people going.
This is with an i9-7980XE and a Corsair H115i cooler...

If you don't want to tinker with BIOS settings, the only required setting for macOS to boot is in BIOS to set CSM Support to disabled (see page 61 of the manual). There are no other changes required to get you doing.
Of course, you should enable XMP.

Playing with light OC, just to achieve the best results for my needs (that is high low-core count frequency tasks) while keeping the temperature in check. Compilation of my work project take around 7 minutes, temperature never exceed 85C during that time.
https://browser.geekbench.com/v4/cpu/7253301
Intel Speed Shift does works with the iMacPro,1 setting, CPU goes down to 1.4GHz at idle and around 14W CPU usage (as per Intel Power Gadget)

MIT
-> Extreme Memory Profile (X.M.P): Profile1

MIT -> Advanced Frequency Settings -> Advanced CPU Core Settings
-> Intel Turbo Boost Technology : Enabled
-> Turbo Ratio (1-core Active): 47
-> Turbo Ratio (2-cores Active): 47
-> Turbo Ratio (3-cores Active): 46
-> Turbo Ratio (4-cores Active): 46
-> Turbo Ratio (5-cores Active): 42
-> Turbo Ratio (5-cores Active): 42
-> all to 16: 42
-> Turbo Ratio (17-cores Active): 40
-> Turbo Ratio (18-cores Active): 40

-> Intel Turbo Boost Max Technology 3.0 : Enabled
-> Intel Speed Shift Technology : Enabled
-> Enhance Multi-Core Performance : Enabled
-> C6/C7 State Support : Enabled
-> Package C State Limit : C6
-> CPU EIST Function : Disabled
-> Energy Efficient Turbo : Disabled

BIOS
-> CSM Support : Disabled

Peripherals -> USB Configuration
-> XHCI Hand-Off : Enabled
Peripheral -> Thunderbolt Configuration
-> Security Level : SL0 - No Security

Clover configuration:
in config.plist Boot settings you *must* have npci=0x2000 checked.
dart=0 should be checked (if you have VT-d enabled in the BIOS which is the default)

BTW.. I just realised one more thing..

Why your CPU load table has been chosen as implemented?

While you significantly and likely unnecessarily overclock cores 1-4, you significantly under-clock all other cores...

Why didn't you choose a more equilibrated CPU Load Table distribution?

Any explanation, which helps in understanding your decision?

The other question would be what in your actual BIOS settings equals to the ASUS CPU Core Ratio BIOS functionality "Sync All Cores" ...

Cheers,

KGP

 

[RuleBreaker01]

Well, NO when I disconnect and reconnect the screen, my primary screen remains black. So it does not reconnect.
BUT, I still are able to "work" normally on the second screen, and the menu bars is always visible/usable on both monitors.
Even if the 1st primary monitor does not reconnect, I'm able to use the second one as the "new" primary.

OK...
So it's not just me.
This shows that there's something wrong with the native vega support.
I'm guessing this is why my 5K isn't supported there. Typically when used either with my mac pro 2013 or in Windows on that same box, the screen connects momentarily at 2560x1440 and immediately retiled the two screens together. This screen appears as two screens with OS without support. Each 2560x2880.

Why that problem is fixed when using Macpro,6 smbios is very bizarre..

 

[kgp]

OK...
So it's not just me.
This shows that there's something wrong with the native vega support.
I'm guessing this is why my 5K isn't supported there. Typically when used either with my mac pro 2013 or in Windows on that same box, the screen connects momentarily at 2560x1440 and immediately retiled the two screens together. This screen appears as two screens with OS without support. Each 2560x2880.

Why that problem is fixed when using Macpro,6 smbios is very bizarre..

I guess you mix up two things at this point..

One thing is that @prunzi seems to face some problems with hot plug, which is absolutely a minor issue. Everything else is working, also multi-display support..

Remember, that in contrary, @DSM2 reported that his Vega is fully hot plug able also with SMBIOS iMacPro1,1... He currently just does not have 2 monitors for testing the multi-display functionality.

In contrary, you are not able to run your 5K Monitor at all...

Try to connect two monitors different from your 5K display and see if everything works as expected.

If the latter is not the case,

happy debugging

 

[RuleBreaker01]

This should work!

2560x1440 Scaled 2 times

Also which screen is it exactly?

HP z27q.
Setting a custom resolution will never work with those screens. That's not how they work. They are physically like two independent screens that the OS will tile side by side.
Utilities like SwitchResX and so forth are of no use as they just attempt to calculate the modeset for a single cable, which would well exceed the DP 1.2 standard (you would need almost 1GHz horizontal rate).

Anyhow, I've made some interesting discoveries with the usage of the DP ports... I'll post later about it

 

[RuleBreaker01]

Interesting.. although your NVMe load temps are even higher than in my case, you do not seem to face any NVMe performance loss due to a likely thermal throttling.

NVMe load temps of 54 deg C however rather contradict your conclusion that you found the perfect location cooling wise..

Could it be a Pro VS EVO thing then?

I say it's better cooling wise, because the SSD in the M.2 slot is always around 3C more than the other

 

[kgp]

Could it be a Pro VS EVO thing then?

I say it's better cooling wise, because the SSD in the M.2 slot is always around 3C more than the other

Let me try to use the EK NVMe heatsink that I ordered today and I will report back tomorrow, o.k.?

 

[RuleBreaker01]

BTW.. I just realised one more thing..

Why your CPU load table has been chosen as implemented?

With the asus sync all core option, only using 42 gave me acceptable result. 43 was making the temperature reach over 90C.

So 43 was too high, 42 okay, but 42 overall isn't that great for tasks using only a single CPU.
I give you an example; when I compile C++ it will typically parallelise things very well, but launching as many compilation tasks are there are CPUS. That spread well with a very high core count processor like the 7980xe.
Then come linking, linking while highly multi-threaded, it only runs on a single process. It's done at the end when there's nothing left to compile. So here the higher frequency the better... So having higher than 42 ratio makes sense.
For core 17 and 18 I reduced the ratio so that temps stays below 85C.
I can see the power usage reaching 350W during a compilation. That's a lot of heat to get rid off.

So this is the rationale behind the values I chose.

While you significantly and likely unnecessarily overclock cores 1-4, you significantly under-clock all other cores...

When only 4 cores are needed, I can afford to OC them greatly, because the power usage is still insignificant then.
I with I could put all of them at 4.8GHz, but I'm not delidding a 2k€ CPU and lose warranty on it.

Why didn't you choose a more equilibrated CPU Load Table distribution?

Any explanation, which helps in understanding your decision?

I hope that the information I provided above satisfy your questions.

The other question would be what in your actual BIOS settings equals to the ASUS CPU Core Ratio BIOS functionality "Sync All Cores" ...

The most I could use with sync all cores was 43. For my workload and typical use, I'm much better off having more detailed flexibility in using more for when only a few cores are used, and use something reasonable for the rest.

Everyone has different need. Me, I'm a programmer. I just want things to compile fast.
I'm guessing with your job and speciality you would have different needs.

 

[RuleBreaker01]

I guess you mix up two things at this point..

One thing is that @prunzi seems to face some problems with hot plug, which is absolutely a minor issue. Everything else is working, also multi-display support..

I'm not mixing up, nor confusing anything. I reported two issues with the Vega as it works in 10.13.3
1- my 5k screen doesn't properly work (though more to come on that later)
2- multi screens with hotplugging do not work.
None of those issues occur with a Macpro,6 smbios.

@prunzi doesn't have a 5K screen, so he can't report on 1, but he reports on 2 too.

Remember, that in contrary, @DSM2 reported that his Vega is fully hot plug able also with SMBIOS iMacPro1,1... He currently just does not have 2 monitors for testing the multi-display functionality.

With the information at hand, it's safe to say that I'll wait for him to try with two screens before accepting that hotplugging works for him

 

[kgp]

I'm not mixing up, nor confusing anything. I reported two issues with the Vega as it works in 10.13.3
1- my 5k screen doesn't properly work (though more to come on that later)
2- multi screens with hotplugging do not work.
None of those issues occur with a Macpro,6 smbios.

@prunzi doesn't have a 5K screen, so he can't report on 1, but he reports on 2 too.



With the information at hand, it's safe to say that I'll wait for him to try with two screens before accepting that hotplugging works for him

That your 5k screen doesn't properly work might not be exclusively the fault of the Vega

@prunzi reports that he is easily able to drive 2x 4K monitors with his Vega apart from some hot plug issues.. Are you?

Vega hot plug functionality with one monitor has already been confirmed by @DSM2. Let's see if he is able to find a second monitor for testing the Vega hot plug functionality for two monitors..

SMBIOS macPro6,1 for me at present is definitely no valuable option.. in any case, your decision..

No idea if it is really worth to commit all efforts you are asking for... hot plug functionality is absolutely negligible in daily life..

Also remember that you initially claimed that Vega multi-monitor support des not work at all with SMBIOS iMacPro1,1, which is definitely not the case!

To emphasise once more the remaining crucial question:

Are you able to drive 2 standard monitors with your VEGA and SMBIOS iMacPro1,1, like @prunzi does?

If the latter is not the case, it would also not be very surprising that your 5K Monitor, which apparently requires 2 DP connections, does not work at all..

You understand what I mean?

 

[kgp]

With the asus sync all core option, only using 42 gave me acceptable result. 43 was making the temperature reach over 90C.

So 43 was too high, 42 okay, but 42 overall isn't that great for tasks using only a single CPU.
I give you an example; when I compile C++ it will typically parallelise things very well, but launching as many compilation tasks are there are CPUS. That spread well with a very high core count processor like the 7980xe.
Then come linking, linking while highly multi-threaded, it only runs on a single process. It's done at the end when there's nothing left to compile. So here the higher frequency the better... So having higher than 42 ratio makes sense.
For core 17 and 18 I reduced the ratio so that temps stays below 85C.
I can see the power usage reaching 350W during a compilation. That's a lot of heat to get rid off.

So this is the rationale behind the values I chose.



When only 4 cores are needed, I can afford to OC them greatly, because the power usage is still insignificant then.
I with I could put all of them at 4.8GHz, but I'm not delidding a 2k€ CPU and lose warranty on it.



I hope that the information I provided above satisfy your questions.



The most I could use with sync all cores was 43. For my workload and typical use, I'm much better off having more detailed flexibility in using more for when only a few cores are used, and use something reasonable for the rest.

Everyone has different need. Me, I'm a programmer. I just want things to compile fast.
I'm guessing with your job and speciality you would have different needs.

I agree with all your reasoning.. But driving 4 cores at frequencies far beyond the stock frequency should overhead these cores tremendously, especially if one considers that you just use a H115i, isn't it? It is not a question of power consumption. It is basically a question of head load within these 4 cores. Or is the heat dissipation by the IHF that fast, that the heat load produced be the 4 cores is immediately spread over the entire IHF, thus the temps of the 4 cores never exceed the critical level of 95 deg C? I mean it is not a question what is the average temperature over the IHF, the question is what is the max. temperature reached at each of the 4 cores?