Cores x Clock

[ricardobjerke]

Does Corona performs better with a high number of cores (but lower clock speeds) or is it better to have a machine with less cores but with higher clock speeds?
I guess that would have something to do with multi threading performance?
Anybody?

[Juraj]

Ondra mentioned it's extremely well multithreaded by now, so it shouldn't matter.

Nonetheless, it's always better to have fewer more powerful cores (considering equal total multithreaded performance in theory) for workstation, generally in practice that solutions fares better in most common tasks which aren't perfectly multi-threaded (or are 'capped' to amount of cores they can utilize).
There is also cap to how many cores you can utilize in regular workstation under consumer OS (non-server Windows).

Fewer high-clocked cores also almost always come with stronger multiplier and turbo for single-core, yielding superior power to single-core tasks (almost everything else you run on computer).

This is also the reason why the "WS" (165W) Xeon 2xxx range is the most expensive (high clocked 8-cores, compared to super low-clocked 14-cores)

[Ondra]

There is also cap to how many cores you can utilize in regular workstation under consumer OS (non-server Windows).

Really? Here they say it is 256 cores: http://answers.microsoft.com/en-us/windows/forum/windows_10-win_upgrade/windows-10-versions-cpu-limits/905c24ad-ad54-4122-b730-b9e7519c823f?auth=1

ad original question: yep, corona is almost perfectly multithreaded during rendering (if you multiply number of cores by frequency, you will get performance in corona, +- 10%).  But rest of 3dsmax is not, so prefer less cores with higher frequency if you are choosing from several options with same cores*freq coefficient

[Juraj]

There is also cap to how many cores you can utilize in regular workstation under consumer OS (non-server Windows).

Really? Here they say it is 256 cores: http://answers.microsoft.com/en-us/windows/forum/windows_10-win_upgrade/windows-10-versions-cpu-limits/905c24ad-ad54-4122-b730-b9e7519c823f?auth=1

Yes, but that pertains up to 2 sockets (which is currently 72 cores I think with existing Xeons). People who bought 4-socket ( E7 4xxx Xeons) run into issues with hypethreading and all-cores utilization in 3dsMax once again, even under WindowsServer.

[Ricky Johnson]

One factor that stays unanswered in that windows thread is that you do need to go above Windows 10 Home in order for Windows to recognise more than 1 CPU.
So, in any pricing comparison between faster single cpu systems and slower dual cpu systems (if that's where the original post is leading), you'd need to account for the price of a premium version of Windows.

[Ondra]

there is no premium anymore AFAIK, only home vs. professional. Home does not have remote desktop, so it is unusable for me anyways. And even if not, the price difference is about 45 euros, which is really nothing in context of buying dual xeon workstation.

[Ricky Johnson]

there is no premium anymore AFAIK, only home vs. professional. Home does not have remote desktop, so it is unusable for me anyways. And even if not, the price difference is about 45 euros, which is really nothing in context of buying dual xeon workstation.

Sorry that was a bad choice of words - I meant premium in the general sense of the word as opposed to the official title (forgot that they used that as an actual title for previous versions).
I seemed to manage to pay £99.99 for the privilege of upgrading from Home to Pro but still, I agree the price difference is fractional and wouldn't really sway decisions at that level.
I thought it was useful knowledge nevertheless as it's not immediately obvious from Microsoft's Windows 10 comparison pages that this limitation exists.

[marcosppr]

Hi, i read what you're saying about core x clock, but at this point i feel a little confused.

I work major time with corona renderer, so im looking for new upgrade for workstation and based on i read here u re saying that is better to have a 2 x Xeon 6 core X5675 3,1 GHz vs 2 x Xeon 8 core E5-2650 with 2 GHz ? Is wise to do the calculation based in nºcores vs clock?

X5675 ->12 c x 3,1 Ghz =37,2 Ghz

E5-2650 -> 16 x 2GHz = 32 Ghz

The best choice is the X5675 for this case (corona render only)?
Thanks

[Njen]

One factor that stays unanswered in that windows thread is that you do need to go above Windows 10 Home in order for Windows to recognise more than 1 CPU.

This is not true. I am running a box with a dual Xeon setup for a total of 20 cores/40 threads on Windows 7.

[EDIT:] Oh, wait I think you meant the emphasis on going above the version of Windows 10, rather than Windows 10 itself. All good then.

[Juraj]

Hi, i read what you're saying about core x clock, but at this point i feel a little confused.

I work major time with corona renderer, so im looking for new upgrade for workstation and based on i read here u re saying that is better to have a 2 x Xeon 6 core X5675 3,1 GHz vs 2 x Xeon 8 core E5-2650 with 2 GHz ? Is wise to do the calculation based in nºcores vs clock?

X5675 ->12 c x 3,1 Ghz =37,2 Ghz

E5-2650 -> 16 x 2GHz = 32 Ghz

The best choice is the X5675 for this case (corona render only)?
Thanks

No one is saying that :- ). The mathematics is absolutely sound but more complex:

[All core turbo frequency] x [ amount of cores ] x [ generation multiplier ]

The mathematics work right out of the box only when comparing exact generation ( Haswell-E vs Haswell- E ), but not so much when different generations, like in this case first-generation SandyBridge-E vs old Westmere-EP.
Also, it's sometimes hard to find out the all-core turbo frequency, because Intel only writes single-core turbo in their description, but wikipedia lists all the multipliers.

Anyway, it's supposed to be just general estimate, I personally always use Cinebench R15 scores.

I don't really have time to find the numbers for your two particular CPUs, but although the odds are against the 2650v1 because of low-clock (Max single turbo is 2.8 and I think the all-core might be like 2.3), SandyBridge was big upgrade from Westemere, so it will probably hold up both in single and multi-core performance just fine. Might even come up better.