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GTX670 Tri-SLI - bottleneck?

Last response: in Graphics & Displays
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February 13, 2013 10:46:59 AM

I'm using EVGA Superclocked GTX670 Tri-Sli on an IvyBridge i7 3770K @ 4.7ghz. The Mobo is an Asrock Z68 Extreme 7 Gen 3.

GPU-Z is reporting the first card at x16/2.0, the second and third at x8/2.0

A few questions:

1. Is my CPU bottlenecking this? I think I could get 5.0ghz, but 4.7ghz was easy and I'm still on H100 cooling - don't want to go custom loop
2. Is my Mobo bottlenecking this? It advertized PCIE 3.0 but I think that's only for single GPU in the first slot with an Ivy Bridge chip. Or am I wrong?
3. Would RAM bottlneck this? I have 32gb RAM but they are standard 1600 chips - I'm not OCing it at all.

Thanks in advance.
a c 80 Î Nvidia
February 13, 2013 1:37:01 PM

Whether or not your CPU is bottlenecking your 670's is up to your resolution. Given you did not mention one, that leads me to believe you have 1080p, as that is what most people have these days.

The short answer is "yes, most of the time".

The long answer is you have far too much GPU power for a single 60hz 1080p monitor and your CPU is plenty fast for the monitor, you just have wasted GPU power.
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February 13, 2013 1:38:11 PM

My resolution is 3420x1920 (three 27" monitors in portrait mode) via nVidia SLI Surround.
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February 13, 2013 1:42:28 PM

You should be getting 60 FPS in pretty much all games unless you push the AA to high and get vram issues. The CPU might be bottlenecking your FPS to something like 80 FPS... where your GPU might be able to push 100 FPS... But if you are on 60Hz monitors you only can display 60 FPS anyway so it doesn't matter. Turn on Adaptive Vsync and don't worry about your "bottlenecks" unless you are seeing fps sub 40.
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February 13, 2013 1:44:51 PM

thepregnantgod said:
1. Is my CPU bottlenecking this? I think I could get 5.0ghz, but 4.7ghz was easy and I'm still on H100 cooling - don't want to go custom loop

A bottleneck wouldn't change the standard being used, just slow down the one in use.

Quote:
2. Is my Mobo bottlenecking this? It advertized PCIE 3.0 but I think that's only for single GPU in the first slot with an Ivy Bridge chip. Or am I wrong?

Right on all counts. You're using a Z68 board, which was before PCIe 3.0 became the standard. As a result, motherboards didn't really have the bandwidth for proper implementations. Your board is very likely PCIe 3.0 with single cards in the top slot only (and yes, you need an IVB chip to get PCIe 3.0 as well).

Quote:
3. Would RAM bottlneck this? I have 32gb RAM but they are standard 1600 chips - I'm not OCing it at all.

32GB is about six times more than you'll ever reasonably use, unless you're doing rendering or photo/video editing or using a RAM disk. It also won't impact which PCIe standard your board uses.
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February 13, 2013 1:45:28 PM

Cool.

So the PCIE 2.0 x16/x8/x8 doesn't really matter?

As for vRam all the cards have 4gb each.

Yes, my monitors are 60hz - so I know I'll be maxed at 60fps. I'm currently playing Skyrim at that resolution on Ultra settings - with only a few stutters - but I wanted to make sure from others who have more experience.
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February 13, 2013 1:47:12 PM

@willard, I am using a 8gb RAM disk and do some rendering from time to time (plus the RAM was soooo cheap.)
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February 13, 2013 1:49:04 PM

PCIE 2.0 x8 will only reduce your performance by maybe 2-3% - nothing to worry about. as for Vram the main issue is going to be the memory bandwidth not so much the amount - try setting your memory clock offset to something between +300-500 on each card if you can.
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February 13, 2013 1:50:42 PM

Memory offset? I OC'd my 570s before but the 670s seem to be a little different with something like a "boost." I'll pull up the EVGA tool and try that.
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February 13, 2013 2:02:23 PM

I would say your 1600 RAM would be a bottleneck, and also the 8x crossfire bus with triple SLI, the 670s are gonna definetely bottleneck. Faster ram would help a bit too
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February 13, 2013 2:05:41 PM

Didn't toms do a review on ram recently? I thought it showed that 1600 ram vs 2133 had very little improvement and no improvement in most titles.. I'll see if i can find it. Oh and going from 2.0 x16 to 2.0x8 is only like 2-3% performance difference - not enough to really worry about.

Found the review.... It was using an AMD CPU... So no help really. Anyway I know ram speed is much less of an issue with intel builds. AMDs do see better performance with higher ram speeds while intels see much less - no point in really going above 1600 on intel system so you are fine.
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February 13, 2013 2:06:05 PM

1600RAM vs 2133RAM? Most of the articles I read said the difference is minimal, if at all.
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February 13, 2013 2:07:56 PM

Best answer selected by thepregnantgod.
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February 13, 2013 2:09:11 PM

icemunk said:
I would say your 1600 RAM would be a bottleneck

RAM speed has very little impact on performance. Going faster than DDR3-1600 does improve your framerates, but it's pretty small. I consider this to be a worthwhile investment, since it's typically a 0.5% - 1% increase in computer cost, for a 1%-3% performance gain. That's a win in my book.

Quote:
and also the 8x crossfire bus with triple SLI, the 670s are gonna definetely bottleneck.

Actually, not really. PCIe has so much more bandwidth than is necessary it's insane. Basically, the standard is 2 generations ahead of the cards, in terms of bandwidth. We're only just now getting cards that see major performance degradations on PCIe 1.1.
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March 16, 2014 5:13:08 PM

Hi.
The pcie 2.0 at 8x can be a bottleneck, and probably it is, depends on how much bandwidth the game demands (I remember on a review in this site that dirt3 was one of the most demanding and bottlenecked by pcie2 8x), depending on games I think can bottleneck up to 20-30% of performance. But your motherboard is a PCIE 3.0, you only need to unlock it with a patch. So this wont be a problem. Google for it ;) 

If the cpu is a bottleneck I can't answer for sure, but usually more clock corresponds to more fps. I have 3 gtx titan and cpu 3970x at 4.6ghz and I would love to have a cpu with 30% more power. Have same res as you only in landscape instead than portrait.

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March 16, 2014 5:14:33 PM

bystander said:
Whether or not your CPU is bottlenecking your 670's is up to your resolution. Given you did not mention one, that leads me to believe you have 1080p, as that is what most people have these days.

The short answer is "yes, most of the time".

The long answer is you have far too much GPU power for a single 60hz 1080p monitor and your CPU is plenty fast for the monitor, you just have wasted GPU power.


So in your opinion a guy with triple sli would have a single hd monitor................................

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March 16, 2014 5:42:05 PM

thepregnantgod said:
I'm using EVGA Superclocked GTX670 Tri-Sli on an IvyBridge i7 3770K @ 4.7ghz. The Mobo is an Asrock Z68 Extreme 7 Gen 3.

GPU-Z is reporting the first card at x16/2.0, the second and third at x8/2.0

A few questions:

1. Is my CPU bottlenecking this? I think I could get 5.0ghz, but 4.7ghz was easy and I'm still on H100 cooling - don't want to go custom loop
2. Is my Mobo bottlenecking this? It advertized PCIE 3.0 but I think that's only for single GPU in the first slot with an Ivy Bridge chip. Or am I wrong?
3. Would RAM bottlneck this? I have 32gb RAM but they are standard 1600 chips - I'm not OCing it at all.

Thanks in advance.


If you disable surround you can check by the windows monitor settings, probably your monitor supports more than 60hz at 1080p. Mine old ones, the asus ve278q cud go up to 72hz. So you can setup higher hz by every monitor individually, then re-enable surround. Im not sure if it will keep the settings.
http://www.youtube.com/watch?v=8sXeSwe1_dU

Anyway if you play fast fps especially in multiplayer I suggest you to keep fps over 80, in this case frametimes go down, in the case of a heavier load you'll go down to 50-60 but not to 30-40. Depends how much you like fps drops while you are surrounded in multiplayer ;)  lol.


I saw by a review the change from 1600mhz is the last one that is worth (don't upgrade ram with 1833/2133/2400 the gain is little), changing to 2400 will give you maybe 3-6fps but if performance is important I would buy 2400mhz memory. ;) 

I think you find more answers by overclock passionates ;)  you have an enthusiast pc with a resolution and a card setup out of ordinary (not mainstream). The most answers you will get don't fit, unless you get them by others that have experience with pc with multi sli and high overclocks.


If you wanna improve performance or temps with little changes, change the termal paste of the gpus, I had 5degree lower temp on my old gtx 680 cards with changing the paste to the silver artic 5 (not sure about the name). If you wanna get 30% less temps on the cpu, delid it (you find guides online), but then use liquid metal termal paste. You'll see a huge temp drop.
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