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Dual CPU - how many watts?

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February 18, 2013 11:01:45 AM

I posted this question earlier and just want to confirm with you guys:

I am running 2 Intel Xeon E5645 2.40GHz CPU's on a ASUS Z8PE-D12X Mainboard with a GTX680. The Vendor I bought it from put in a 750W PSU (bronze). The problem is that I experience performance issues (especially when gaming).

The vendor states that the PSU is more than enough. Someone on the forum told me to go with at least 850W (preferably gold). Is that correct?

I wanted to double check with you guys so I am not coming off as a complete idiot when arguing with the vendor!

thanks!

More about : dual cpu watts

a c 118 à CPUs
February 18, 2013 12:18:45 PM

A 750W, if high quality, should be able to power your system.
What is the make and model of the current PSU?
Finally, what performance issues in particular are causing concern here? Are you running 8 sticks of ram?
a b à CPUs
February 18, 2013 12:35:04 PM

The power supply certainly doesn't cause the performance issues. Reason for that is the lame single tread performance of the xeons. And as C12Friedman said, 750W should be able to power your system, because the xeons only need 80w each and i'm sure you are not using half of the cores.
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February 18, 2013 12:56:21 PM

C12Friedman said:
A 750W, if high quality, should be able to power your system.
What is the make and model of the current PSU?
Finally, what performance issues in particular are causing concern here? Are you running 8 sticks of ram?


its a corsair CX750 PSU.

i am running 6 sticks of ram with each 4GB.

the thing is that the rig is mainly used for 3D animation work, where it basically is performing fine. but the occasional game drives me nuts. older games like dragon age origins and the witcher 2 are causing weird problems. while the cpu load runs at 5% and the gpu load at a max of 40% i get frame rate drops all the time, like every 3-5 seconds - frame rate drops to 0 goes up to 60 again i'm running around a bit in the game - frame rate drops to 0 - goes up again to 60. if i stand still i get a solid 60fps.

when the rig is rendering 3D he's really fast and powerful. I love the 24 cores doing its work in C4D. i am just disappointed that with such a modern and powerful rig i can't play games in medium settings smoothly and trying to find a solution for that.

here's my previous post. where someone told me that the gtx680 will suck so much power that my PSU can't keep up.
February 18, 2013 12:57:43 PM

noidea_77 said:
The power supply certainly doesn't cause the performance issues. Reason for that is the lame single tread performance of the xeons. And as C12Friedman said, 750W should be able to power your system, because the xeons only need 80w each and i'm sure you are not using half of the cores.



mhhh. can you elaborate that? thanks!
a c 108 à CPUs
February 18, 2013 2:39:26 PM


The 2 x Intel Xeon E5645s is likely killin' yah when combined with NUMA.

Open your task manager and check your page faults.

February 18, 2013 3:01:24 PM

Wisecracker said:
The 2 x Intel Xeon E5645s is likely killin' yah when combined with NUMA.

Open your task manager and check your page faults.



i can't check right now. since i am rendering in After Effects. i checked the page faults column though and did ready about it a bit. so it seems that is a bottle neck of some kind.

e.g. after effects page fault is way above 20.0000

i am a long time mac user and recently switched to a pc. i have no clue what that means? what can i do about that?

thanks
a c 108 à CPUs
February 18, 2013 3:26:25 PM


firewireflow said:
i can't check right now. since i am rendering in After Effects. i checked the page faults column though and did ready about it a bit. so it seems that is a bottle neck of some kind.

e.g. after effects page fault is way above 20.0000

i am a long time mac user and recently switched to a pc. i have no clue what that means? what can i do about that?

thanks


It's just a by-product of the 2/4/8 CPU platform arch, the software and the OS. Multi-socket platforms generally have specific software written to optimize the set-up. A server or *Pro* OS may provide some benefit to you, but I'm currently 5+ years behind on that tech :lol: 

Here's the deal: You're digging along and CPU1 reaches out to its DIMM bank, misses and faults, and has to go looking in the CPU2 DIMM bank. I like to call this NUMA Hell :D 

If you're lucky you will muddle thru your output with little impact - the faulting will remain at a consistent level. In some instances I recall that the faulting would seemingly compound upon itself and get worse as the output time grew longer.

NUMA Hell.

The future good news is ... DDR4 and IOMMU will likely help this immensely

(won't do you any good right now, though)




February 18, 2013 4:07:30 PM

i am getting about 1300 soft page faults per second playing witcher 2.

the weird thing now is that playing the game in window mode seems to eliminate the frame rate drops.

is there anything i can do about page faults?
a c 108 à CPUs
February 18, 2013 4:12:34 PM


Is is possible for you to set up different profiles in your BIOS ?

I would set up a separate profile that shuts down the second socket and boot to that setup for gaming.

See if that helps your overall gaming performance.

a b à CPUs
February 19, 2013 3:22:19 PM

firewireflow said:
mhhh. can you elaborate that? thanks!

I think you already got some more info on that from the other posters. The general problem is, that only you design / rendering programs are written for a machine like this. Most of the older games are not even aware of more then one core. Sometimes the special bios-profile with only one cpu enabled helps. Sometimes it simply helps to goto the taskmanager and associate the game process with only one logical core. That at least prevents it from jumping from one cpu to the other, what creates most of the page faults.
!