Dual GPU Performance

dexter254 · Sep 20, 2018

So this is the rig i intend on building. https://pcpartpicker.com/user/Karax/saved/#view=4RNyXL. Focus is on the motherboard; Asus - Prime Z370-A ATX LGA1151 and the AIO cooler; Corsair - H100i v2 70.7 CFM Liquid CPU Cooler.

I intend on adding a GTX 1060 6Gb, 16Gb Ram and 1 250Gb SSD and 1Tb HDD to make a 2 user rig using UNRaid. Got 2 questions:

1. is the motherboard sufficient to run the 2 GPUs i.e the Gtx 1060 and Gtx 1080 (8gb) given that the bus will be x8 bus speeds for each?
2. will the AIO cooler be sufficient for the CPU given the task of running the VMs in UNRaid?

Darkbreeze · Sep 20, 2018

Is there a specific reason why you want to run those two graphics cards together? You realize you can't SLI them right?

If you just need additional monitor support, I'd run just one of them, along with the integrated CPU graphics.

One 8700k is really not enough to run both those graphics cards independently for two gamers to use the same machine (Not well anyhow when one GTX 1080 pretty much needs the whole 8700k to itself.) PLUS you'd need more like a 1000w PSU of really good quality to run both those cards. An 850w unit is probably not going to cut it. Maybe, but it's going to be running near capacity all the time and it's not going to last long like that.

dexter254 · Sep 21, 2018

Darkbreeze :

They are for 2 VMs that i'll setup in UNRaid and will passthrough each card to each VM

Darkbreeze · Sep 21, 2018

So, you're trying to do the LTT thing? It's still going to use a lot of CPU resources. Probably more even than running it normal as you've got the extra CPU overhead of the VM to factor in on top of the game engine, OS and UNraid operations. More importantly though, I really think you'll run into serious issues with power delivery with an 850w unit.

As far as your other questions go, yes it will be capable of running both cards at x8 mode, which of course is going to be a hit on the performance of both cards. That AIO is also plenty for that CPU, even with some fair amount of overclocking. Not that you'll be wanting to overclock anything with a PSU that is already going to be near or above capacity as it already stands.

volkgren · Sep 21, 2018

I've done crypto mining with multi-GPU rigs and used energy meters to monitor power consumption on various GPUs and systems, I seriously doubt an i7-8700 + GTX 1080 + GTX 1060 will come anywhere close to 850W. No way it's going over 700W.

An overestimate:

i7-8700K - 150W
GTX 1080 - 250W
GTX 1060 - 150W
System - 150W
Total - 700W

and average load on each of those is usually less than that. Not sure where you're coming up with your idea that 850W G3 won't be enough. Typical load would probably be closer to 550W.

Darkbreeze · Sep 21, 2018

Mining and gaming are entirely different when it comes to usage and power consumption. They don't even utilize the GPU in the same way.

Even going off the base power consumption, not factoring in spikes, overclocking, increased consumption from age (Yes, this happens with practically ALL cards) or the fact that unlike with SLI/Crossfire, these cards would BOTH be functioning at full capacity any time they are under a full load, unlike SLI where they alternate the render between cards, it would still be 75+75+75+150+150=575w JUST for the slots and connectors, plus probably another 150w for the rest of the system, at least.

That's 750w actual potential consumption, not counting spikes which are always a factor or the idea that you want ~40% overhead, if you have any realistic expectation of the PSU lasting more than a year or two, even with a great unit. No way an 850w unit meets those expectations so you either end up with an overworked unit that runs near capacity all the time and is constantly loud anytime both cards are being used, or in fact, problems resulting in reduced performance.

Will it work. Yeah, most likely. Is it a recommendable configuration, I don't think so. Not with anything less than about 950w. And those need to be good, clean watts. Not some Raidmax 1000w unit.

volkgren · Sep 21, 2018

Darkbreeze :

You're gonna have to explain that. You're saying the two GPUs together will use 575W? What exactly are you adding there?

Darkbreeze · Sep 21, 2018

Two slots, one for each card, is 150w.

The GTX 1060 uses a six pin connector, that's another 75w.

The GTX 1080 likely uses two 8 pin connectors, that's 300w.

300+75+150=525w. Not sure where I got the other 50w from. My mistake. Still, that's 525w for JUST the cards. Give that 40% headroom and for just the cards plus a standard extra 40% you've got over 700w and you haven't even begun to include anything for the system, for spikes or for overclocking if there is going to be any. Just an actual draw of 525w from the cards plus probably another 150w for the CPU, motherboard and other hardware, is enough to make an 850w PSU a rather less than desirable configuration.

dexter254 · Sep 21, 2018

volkgren :

That's what i thought too. Did the math and the power consumption does come to the 700w mark. LTT used an 850w psu and as I remember correctly he mentioned no issues of power drain of the psu.

dexter254 · Sep 21, 2018

Darkbreeze :

Mining and gaming are entirely different when it comes to usage and power consumption. They don't even utilize the GPU in the same way.

Even going off the base power consumption, not factoring in spikes, overclocking, increased consumption from age (Yes, this happens with practically ALL cards) or the fact that unlike with SLI/Crossfire, these cards would BOTH be functioning at full capacity any time they are under a full load, unlike SLI where they alternate the render between cards, it would still be 75+75+75+150+150=575w JUST for the slots and connectors, plus probably another 150w for the rest of the system, at least.

That's 750w actual potential consumption, not counting spikes which are always a factor or the idea that you want ~40% overhead, if you have any realistic expectation of the PSU lasting more than a year or two, even with a great unit. No way an 850w unit meets those expectations so you either end up with an overworked unit that runs near capacity all the time and is constantly loud anytime both cards are being used, or in fact, problems resulting in reduced performance.

Will it work. Yeah, most likely. Is it a recommendable configuration, I don't think so. Not with anything less than about 950w. And those need to be good, clean watts. Not some Raidmax 1000w unit.

I hear you. So besides a 950w+ PSU which motherboard would you recommend for the GPUs to operate at their optimum?

dexter254 · Sep 21, 2018

Anyone else with thoughts on this please chip in and share. Help make a 1st time Rig assembly a happy one

Darkbreeze · Sep 21, 2018

Hey, it's your system. You are certainly entitled to do exactly as you please. I'm only in the habit of offering recommendations based on experience of my own, and what I've seen from others testing. Also, in keeping with "best practices", which is commonly believed to include the aforementioned headroom of 40% when selecting a PSU.

If you don't mind the PSU being at max fans, or having increased levels of ripple, electrical noise or voltage regulation issues because it's nearly always operating in the upper 20% of it's capacity, that's certainly your prerogative. I just think that the price difference between a decent 850w unit and a similar 1000w unit isn't that much and is more than obviously a good idea, not that the entire configuration you're planning from start to finish is a good idea to begin with.

I think there are far better ways to allow two people to game than by attempting to do it all on one system. There's enough troubles with gaming rigs when only one person is using them, much less splitting it's performance in half and adding the demands of additional software to it in order to even make it work. But it may work out exactly as you hope it will. I think I'd simply build a second cheaper system for the other graphics card.

dexter254 · Sep 21, 2018

Darkbreeze :

I think placing the topic under pc gaming may have been deceiving a little. Thing is the system isn't primarily for gaming but rather rendering and 3D designing mostly in interior design and architecture- though gaming will still be a part of it but not the two GPUs at the same time. I do agree with you the 1000w PSU is definitely a recommended 1-i've redone the math with overclocking factored in and the system in total draws up to 790w, so 1000w PSU it is. Rethinking to go with a GTX 1080 instead of a 1080Ti as the latter seems overkill to me. What do you think?

Darkbreeze · Sep 21, 2018

At what level of expertise do you plan to do the 3D and rendering work? Is this professional grade stuff or just hobby based fundamental applications?

Is is work derived or just something you do for kicks?

dexter254 · Sep 22, 2018

Darkbreeze :

Starting as more of a service for guys so will be kinda professional stuff, planning on using Lumion render software in addition to others.

Darkbreeze · Sep 22, 2018

Well, obviously there are some performance differences between the 1080ti and 1080, but since neither of them is a workstation card with 3D or modeling application specific features anyhow, I think you're right that the 1080 is probably enough, maybe even more than enough, but certainly not too much.

There is actually a killer deal on a GTX 1080 right now, about 100 bucks less than any other bonafide deal on a new card from that series that I see anywhere. This would be very hard to beat, if you have the money to pull the trigger on one during the 5 days or so, unless they run out before then which wouldn't surprise me so if you want and can get one, I'd do it right away.

This same card was about 900 dollars or more two months ago. It was two hundred dollars more than this two weeks ago.

https://www.newegg.com/Product/Product.aspx?Item=N82E16814125880&utm_medium=Email&utm_source=EXPRESS092218&cm_mmc=EMC-EXPRESS092218-_-EMC-092218-Index-_-DesktopGraphicsCards-_-14125880-S0B&ignorebbr=1

volkgren · Sep 22, 2018

Here's the same GPU for a even bigger discount with a promo code. - https://promotions.newegg.com/NEemail/Sep-0-2018/EXPRESS_cbmNLCT_22/index-landing.html?utm_medium=Email&utm_source=EXPRESS092218&cm_mmc=EMC-EXPRESS092218-_-EMC-092218-Index-_-E0A-_-feature&et_cid=45621&et_rid=12344976&et_p1=&email64=am9obi5rLmZpbGVzQGdtYWlsLmNvbQ==

That 1TB 860 EVO is also a good deal.

I'm not sure if you can even see that link, it's from my email subscription, which is free for anyone to sign up.

Darkbreeze · Sep 22, 2018

That's the same price I meant to post it as. Usually when I get those email bargains, it's showing at the same price when I visit the product page. Either way, it's still a great deal on a really good card.

dexter254 · Sep 23, 2018

Darkbreeze :

Well, obviously there are some performance differences between the 1080ti and 1080, but since neither of them is a workstation card with 3D or modeling application specific features anyhow, I think you're right that the 1080 is probably enough, maybe even more than enough, but certainly not too much.

There is actually a killer deal on a GTX 1080 right now, about 100 bucks less than any other bonafide deal on a new card from that series that I see anywhere. This would be very hard to beat, if you have the money to pull the trigger on one during the 5 days or so, unless they run out before then which wouldn't surprise me so if you want and can get one, I'd do it right away.

This same card was about 900 dollars or more two months ago. It was two hundred dollars more than this two weeks ago.

https://www.newegg.com/Product/Product.aspx?Item=N82E16814125880&utm_medium=Email&utm_source=EXPRESS092218&cm_mmc=EMC-EXPRESS092218-_-EMC-092218-Index-_-DesktopGraphicsCards-_-14125880-S0B&ignorebbr=1

Thanks bro!

Darkbreeze · Sep 23, 2018

For sure.

Dual GPU Performance

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