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Xeons possibly underperforming???

566 views 8 replies 6 participants last post by  Duality92 
#1 ·
Hello I'm new here

I have recently bought 2 hp z260 machines for use as 3d render nodes - my first time with windows machines.
Both machines are made from second hand components - both have identical spec:

2 x e5 2680 v1
32gb ram (4x8gb)
Windows 10 pro

I believe that the machines are under performing in comparison to my iMac and MacBook Pro.
I use cinebench as a guide to compare the chips

iMac has i7 6700k 4ghz quad core - cinebench 870
Mbp has i5 2.4 ghz quad core - cinebench 462

The pcs have cinebench score of 2010

My expectation was that the Xeon machines would each render images more than twice as fast as the iMac
Since the Mac book pro renders roughly half the speed of iMac.

However performance from pcs is consistently disappointing - roughly 10% faster than iMac.
This seems incorrect as each Xeon machine has 16 x 2.7 ghz - whereas iMac has 4 x 4 ghz

When I run pcs the task manager performance is 100% during render (up to 3.07ghz) on all 32 virtual cores (hyper threading is on)

Is there anything I can do with drivers/software to boost the speed?
Is there an issue with only having 2 boards ram per chip? Is it possible that this is throttling the cpu efficiency?
Even though the RAM usage in task manager while render is only about 20%

Am I daydreaming? Should the results be better?

Many thanks in advance
 
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#3 ·
MBP has quad core i5? Doubt it, it'll be a dual with HT
What cpu model is it..

What clock speed is your iMac running at during bench? Use Intel Power gadget in mac OS

Run Cinebench in single-core mode and see if the math checks out
 
#5 ·
I have just done some more tests between iMac and pc (I don't have mbp to hand)

iMac - intel power gadget - while rendering between 3.9- 4.0 ghz

CB multi - 852
CB single - 169
Mp ratio - 5.03 x

PC - task manager - while rendering between 3.01 - 3.08 ghz

CB multi - 2095
CB single - 122
Mp ratio - 17.23 x

I don't understand the maths from here on in - and don't know what mp ratio is - does this seem normal?
And if so why slow renders in c4d and vray?
 
#6 ·
Everything looks normal. Your 6700K is running approximately 30% faster compared to your Xeons. That explains a large chunk of the difference in CB single results. The rest of the difference can be explained by the fact that you are comparing 5 year old Xeon - Sandy Bridge technology to new Kaby Lake technology. Rendering programs like Cinebench are able to take advantage of all of the improvements that Intel has been making each generation. For a fair comparison, drop your 6700K down to about 2.8 GHz and its single thread performance should be on par with your Xeon's single thread performance running at 3.0 GHz to 3.1 GHz.

The Mp ratio is just your multi score divided by your single thread score (852 / 169 = 5.04)

The 6700K is only a 4 core CPU. Hyper threading gives you a little bit of extra performance but 8 hyper threads only improves performance in this benchmark by a factor of 5 times. That gives you a factor of about 5/8 or 62.5%.

Your dual Xeon system has 32 threads. 62.5% of 32 = 20 so in a perfect world, a Cinebench Mp ratio of about 20 for your Xeons should be expected. You have an Mp ratio of 17.23 which basically confirms the laws of diminishing returns. Sure you can throw more cores and threads at a problem but having 32 threads is not going to give you 32X the performance, at least in this benchmark. It is also likely that new hyper threaded Kaby Lake technology is better than hyper threaded Sandy Bridge technology. Your results are not showing anything unusual at all.
 
#7 ·
Hi again thanks for the brilliant detailed response. It is really helpful and I will reread carefully several times.

I need to build some render computers and would like to know your advice for best cpu for buck - second hand chips are ok.

The other issue I am having is heat - with several computers in my studio it's going to be very hot. Is there a newer chip with better performance/heat efficiency?

I am happy to build computers myself - but don't have mega budget.

The dual Xeon machine cost just under £950 - made up of refurbished parts - is there a build which could get anywhere near this in cost for better efficiency/heat?

Many thanks
 
#8 ·
Quote:
Originally Posted by eynsham View Post

Hi again thanks for the brilliant detailed response. It is really helpful and I will reread carefully several times.

I need to build some render computers and would like to know your advice for best cpu for buck - second hand chips are ok.

The other issue I am having is heat - with several computers in my studio it's going to be very hot. Is there a newer chip with better performance/heat efficiency?

I am happy to build computers myself - but don't have mega budget.

The dual Xeon machine cost just under £950 - made up of refurbished parts - is there a build which could get anywhere near this in cost for better efficiency/heat?

Many thanks
If you're running processors at high load in several computers the only way to try and escape the heat factor is air condition the room with a dedicated unit. doesn't matter if you have a 5 year old cpu or a brand new one, they all produce heat under load and that heat has to be dissipated from the computer case(s).
If you're not looking forward to being in the same room with multiple computers producing heat and noise along with an AC unit producing noise then I would look into putting the computers in their own isolated room and remote into them from a more user friendly, non heater type computer like a laptop or single desktop.
 
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