[Ian Mapleson]

For using multiple GPUs with AE, there’s no need to use SLI/CF connectors, it will work fine
without them, ie. multiple 580s are ok without being directly linked.

The performance you’re seeing though is perfectly normal. A 580 beats all 700 series cards except
the 780 Ti for most CUDA tasks. See my earlier posts in this thread for detailed explanations.

Ian.

——–
SGI Guru

[Ian Mapleson]

Andrea,

A P55 system! Cool! Hmm, just curious, what happens to the render time if you exclude
the GTS 450 from the CUDA pool? (configurable in NVIDIA Control Panel)

Ian.

——–
SGI Guru

[Ian Mapleson]

Very interesting! Thanks for the info! What was your old rig? Is there a post in this
thread somewhere? I’ll have to search…

Ian.

——–
SGI Guru

[Ian Mapleson]

Excellent info thanks!!

Just curious, what do you get for my test? (Frame 96 only)

https://www.sgidepot.co.uk/misc/cuda.101.zip

I’m guessing it’ll take about 10 mins with three Titans.

Also, what do you get for the Arion 2.5 test?

Ian.

——–
SGI Guru

[Ian Mapleson]

John Garland writes:
> … but as for the cards themselves I am sure if they only needed eight lanes they would
> only have made the card with eight lanes. …

That’s not how such cards are made at all. 😀 They’re all just natively x16 of whatever PCIe
revision.

> It of course depends on the processor and board. i7-3930k support 40 pcie lanes. throw
> a third card on it and you are at 48 lanes. …

That doesn’t matter if the board has PCIe switches, and many do.

> … I think your own testing showed how much worse the 2600 was with two and three cards.

I only have a 2700K atm.

> my ram from 48 to 96 GB it didn’t help at all. …

So far I found the biggest difference for GPU rendering was made by the RAM clock. In one
case, dropping the RAM from 2133 to 1866 increased the render time by 10%.

However, I’ve not tested PCIe speeds. Will try this at some point.

> Dual cpu isn’t necessary with a 17-3930 and two cards, but if you want to get the most out
> of three cards, it will be needed.

For AE, that I can well imagine, but this conclusion is AE specific. Other test like Arion
don’t show such dependencies at all, ie. the scale nicely irrespective of the platform. I’ve
alrady observed with other tests that AE does not properly exploit multiple GPUs in numerous
cases, it’s just not written that well, especially since it doesn’t offer any kind of round-
robin option.

Ian.

——–
SGI Guru

[Ian Mapleson]

Depends on the mbd; I use the P9X79 WS, which does not have any lane disadvantage,
or at least not with two anyway.

Besides, there’s no evidence at all just now that this test remotely requires any
significant degree if continuous PCIe traffic whatsoever. We’re making unwarranted
assumptions here and that’s unwise if the info we post is to be useful in the
decision making processes of potential readers. Proper analysis is required.

Ian.

——–
SGI Guru

[Ian Mapleson]

That’s an astonishly good time with just two 580s. It would be very useful to know how
you’re getting such a quicke time than I do with two 3GB 580s, some other aspect of
the system… the dual CPUs perhaps? Which would be odd as this isn’t supposed to be
a CPU test. Storage setup? Hmm, most intriguing.

Ian.

——–
SGI Guru

[Ian Mapleson]

That’s quite good for a single 580! 8)

Note that I just keep hunting for new/used Thermaltake Toughpower units listed
on ebay, 1kW or more. I’ve bought half a dozen 1475W units, saved more than $2K
doing this. Most were new or barely used, listed as normal auctions, won them
for less than half normal new price in every case. The 1475 is excellent, easily
handles four 580s and an oc’d 6-core. For two 580s I’d get a 1kW. This is of course
more than one really needs, but the idea is to have plenty of headroom to ensure
that the feed for the CPU is stable even when all GPUs are under load, plus of
course AE can stress the entire system, so only factoring in load power for the
GPUs is unwise. If it was just a single 580 though then I’d use an 850W PSU.

Ian.

——–
SGI Guru

[Ian Mapleson]

That’s a good price! So did you get the Lightning Xtreme models, with 832MHz core?

What motherboard are you using? I hope you have at least tri-slot spacing, and
good cooling! 🙂

Ian.

——–
SGI Guru

[Ian Mapleson]

Excellent!! That’s a full minute faster than the scores people have posted for 780s. Cool!

Someone posted a quicker 780 Ti a ways back, but I think that was for a heftily oc’d card.

Have you oc’d the CPU? What does it score for Cinebench 11.529 & R15, Arion CPU, etc.? See
how it compares to my data:

https://www.sgidepot.co.uk/misc/tests-jj.txt

(if the page looks mangled in your browser, select No Style for the Page Style option, eg.
from the View menu in Firefox)

Ian.

——–
SGI Guru