quad gtx/rtx with vintage hardware Tweet

[colorcurvature]

Hi, I was thinking about upgrading cpu/motherboard to be able to use 4 gtx/rtx somewhen in the future.
It seems according mobos and cpus need to be chosen with care (#slots, #lanes, price, ...).
There are quite some threads about high-end workstation building around here.

The question is, if no high-end cpu is needed (just basic 3d modelling, rendering on gpu), would not vintage hardware be enough, namely:
- ASUS RAMPAGE IV FORMULA
- i7-3930k (40 lanes)
to support quad GTX/RTX...

I found one thread from 2012 that reads like quad gtx worked well on this motherboard.
The recommendations seem to tend towards high end mobos, but I have not yet understood why...if all magic happens on GPU...

Thanks

[FrankPooleFloating]

I don't think I'd go quite that old. IMO, you'd be better off with a X99-based mobo rather than X79, since X99 seemed to have ton of new bells and whistles when it came out...

[colorcurvature]

X99 brings DDR4, some more USB and SATA options... but nothing that spectacular?
https://www.pugetsystems.com/labs/artic ... ell-E-581/
Is DDR4 better for rendering than DDR3 is?

[FrankPooleFloating]

You're prolly right. I must have fallen victim to all the X99 marketing ballyhoo... Go for it! X79 or bust!

[glimpse]

hi Colorcurvature.

as for CPUs, to put things in perspective, I've tested a lot of different systems with the same GPU(s) on Intel side anything from Z77 to Z390 also 1st and 2nd gen Threadrippers on X399.

One thing to keep in mind, that even if OctaneRender runs on GPUs You still need CPU to move data in and and out and update stuff whiel rendering as image is constructed in RAM (system memory)

As CPU evolved You got not only Clock speed improvements but also IPC - this is small percentage but it stacks up with each generation and thus in the end if You use same modern GPU (let's say 2080ti) in old vs new system, You can already see up to 10% difference in some cases.

when You start to OC CPUs and tune the those systems the gap could get even bigger. For instance, on Z77 the same card was able to give me a bit over 300 in OB, while in Z390 system I was able to squeeze up to 350 in OB (from the same card that I moved from one system to other).

In the end, doesn't not matter if You buy (new) high end older system (X79, X99) or entry level Z370/Z390, You might end up spending similar amount of money (if You want to get similar performance). But if You end up saving money and cutting corners, You most likely are going to loose performance.

In some cases 5 GPU machine, with lower end CPU (or slower old Xeon) could perform worse compared to 4 GPU machine on new platform (using same cards). So in the end You should look not only how much You can save building on old platform, but how much value You are going to get in the end from Your system.

If You pay less, to get less..that's not so good of a deal. It's just a choice that You can take if You choose to. As for other who are using some dual Xeon motherboards with 11 PCIe slots - that's not only for expansion, but also for stability. In some cases those systems do have an edge over gaming gear.

[colorcurvature]

hmm ok i see so 4 GTX and 12% more on each of them is all-in-all like half of an additional card... and the better the cards the greater the gain... hm hm.
on the other hand... is image assembly on CPU not parallelized, is it such a heavy job? i.e. does not max out cpu usage on a 6 core processor? i must admit I have never monitored cpu usage during render... that performance advantage of high-end mobo/cpu might be software dependent?

[colorcurvature]

one more question glimpse if you allow:

regarding x299, the only processor that has enough lanes to handle 4 gtx is actually i9-7900X?
https://techreport.com/review/31986/int ... m-revealed

the additional pcie lanes that x299 brings cannot be used by graphics if I understood correctly, they are for M.2 etc...

so quad gtx on x299 has a base investment of 300EUR for mobo and 500EUR for cpu...

based on your explanation with cpu power affecting overall rendering runtime, would you advise to avoid AMD because of lower single-core performance? at least, AMD cpus seem to have enough PCIe lanes for everyone...