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5.1 Dual graphics card - non-efi preferred slot?

R

rahaney

macrumors newbie
Original poster
May 18, 2014
27
0
Hi all,

I've been using a 980ti hybrid powered by an aux ps and stupidly updated my mac which resulted in the black screen bug. I swapped my 680mac edition back in and sorted it out but was wondering if I can keep them both in?

I remember reading that the 3.1 had an issue with a non-efi card and fan speeds and a recommendation to use slot 2 rather than 1 for this type of card. Does this still hold?

Currently I've got the 980ti in 1 and the 680mac in 2. Would it be better the other way around? I could unplug everything and try it but it's Sunday and I'm lazy so thought I'd ask :)

Many thanks,
R
 
Just make sure you put the primary card (your 980Ti) at the x16 slot. IMO, 680 at which slot doesn't really matter.
 
Does it matter in which order though?

I have 2 x16s in the 5.1 and no other pcie slots in use.

Is anyone running a gt120 or 680mac and a second non-efi card like me?

Many thanks
 
I ran dual GPU for a while. Even though they are AMD card, but that doesn't make much difference.

https://forums.macrumors.com/thread...mac-with-2-d700s.1732849/page-5#post-21722712

For best performance, install both card in the x16 slot. I don't think it make any difference which card go in which slot. HOWEVER, that's based on the card in slot 2 won't affect the cooler of the card in slot 1. In general, separate the cards by at least one slot is better. Therefore, if you also consider cooling, it's better to put the high performance card in slot 1 (980Ti in your case), and the lower performance card in slot 3.

I know slot 3 is a x4 slot, but that doesn't really matter for the 680.
 
My 980ti is a hybrid, so has the extra water fan which I've switched round to pull air in the front of the case across the heatsink, this has worked well so far.

I'm not sure about moving the 680 to slot 3 to increase the airflow or even having the 980ti in 2 so that it has more air around it?

Each of the cards drives a monitor, the 980ti was driving both but in this set up it only has the main one which should give me a couple more fps?
 
Oh yes, I miss that's a hybird card, so cooling should not be a problem at all, you should able to install the 980Ti in slot 1, and 680 in slot 2. But since you mentioned multi monitor and FPS, do you mean you use it for gaming? If yes, I doubt if 680 + 980Ti is a good combination.

I am not sure how the driver / games work with this combination. In worst case, of course crash. However, even no crash, the 680 may draw back the 980Ti. E.g. The 980 Ti can deliver 90FPS, but the 680 can only deliver 45. End up the system lower the 980Ti's output to 45FPS in order to match the 680's performance.

I really don't know, I never try or even study this how this kind of setup working in multi monitor gaming.
 
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Thanks for the reply, yes, that's how I currently have it but I only game on one screen.

At present the 980ti in slot 1 drives 2560x1440 27" display via DisplayPort and the 680 in slot 2 drives a 23" 1920x1080 by dvi.

The unfortunate thing is the nvidia output preference as dvi>hdmi>dp - if I connect the hdmi output of the 680 to monitor 2 to get 75Hz refresh it overrides the dp from the 980ti to monitor 1 which then black screens. The switch to dvi has allowed both to be used but at 60Hz.

I have managed in the nvidia cp to set the OpenGL rendering option to only the 980ti so fingers crossed that limits the gaming to the main monitor, cuda gpus I have left to all as I think the 680 will do a few frames/calcs to assist the 980ti if what I've read was true.
 
Interesting update, I put the 680 Mac in slot 1 and the 980ti in 2 and now I have a boot screen, which I didn't have the other way round.

The downside is my machine runs hotter and therefore louder.

Still, I have had no issues with running el capitan & win 7 x64 via Bootcamp with each card driving their own monitor.

Actually the addition of the 680 adds some computational resource to my physx, with fallout 4 running now at a constant 60fps (shadow distance med).
 
rahaney said:
Interesting update, I put the 680 Mac in slot 1 and the 980ti in 2 and now I have a boot screen, which I didn't have the other way round.

The downside is my machine runs hotter and therefore louder.

Still, I have had no issues with running el capitan & win 7 x64 via Bootcamp with each card driving their own monitor.

Actually the addition of the 680 adds some computational resource to my physx, with fallout 4 running now at a constant 60fps (shadow distance med).
Click to expand...

Doesn't quite make sense to me. The 680 should provide boot screen in whatever slot. Did you always connect the monitor to the 680?

Also, AFAIK gaming cannot utilise 2 different Nvidia GPU (at least not on a single screen). Fallout can either use the 980Ti or 680, you cannot SLI two different GPU. And the 980Ti itself should be powerful enough to give out 60FPS (unless you run the game at super high resolution), doesn't need any help from the 680 (in fact, the 680 can't help anything).
 
I'll swap them round again to see if I get the boot screen for the 680 in slot 2 but it didn't seem to work yesterday.

The Nvidia Phyx can be set to either card, auto or cpu in the settings. In F4 this is to a GPU whereas in the Witcher is sent to the CPU, if sent to a secondary card it frees up performance on the primary, if my understanding is correct.

I use 2560x1440 which only gave me 40fps with a single 980ti on ultra.
 
rahaney said:
I'll swap them round again to see if I get the boot screen for the 680 in slot 2 but it didn't seem to work yesterday.

The Nvidia Phyx can be set to either card, auto or cpu in the settings. In F4 this is to a GPU whereas in the Witcher is sent to the CPU, if sent to a secondary card it frees up performance on the primary, if my understanding is correct.

I use 2560x1440 which only gave me 40fps with a single 980ti on ultra.
Click to expand...

Interesting, I really didn't expect that. Then now I wonder how those guys have GT120 + 980 Ti works.

A never really play around with the Phyx setting, thanks for teaching me about that. I simply assume that's a part of the graphics rendering and cannot be separated. But if the normal physics part can be done by CPU, of course the Phyx can also be done by another compute device.

By the way, 980Ti should do better than that, at least 40FPS doesn't match the general a 980Ti / gaming review's report. Even the ref 980Ti can perform well above that, your hybird should do even better.
fallout-4-gpu-bench-1440-ultra.png


Before you assign Phyx to the 680, did you let the CPU or 980Ti do the job?
 
Nvidia auto'd to the 680, despite the 980ti as the primary. I'll change it and see what happens.

It's possibly lower because it can only run as pcie1.1 rather than 2, or limited by the 3.46Ghz CPU.

I'd be interested in hearing from anyone who also games on the cMP re fallout fps / unigine scores.
 
rahaney said:
Nvidia auto'd to the 680, despite the 980ti as the primary. I'll change it and see what happens.

It's possibly lower because it can only run as pcie1.1 rather than 2, or limited by the 3.46Ghz CPU.

I'd be interested in hearing from anyone who also games on the cMP re fallout fps / unigine scores.
Click to expand...

PCIe 1.1 doesn't affect much and it won't cause a 50% performance drop (in fact, even not 15% in general).

If CPU limiting, let 680 do the Phyx won't help anything. It's still CPU limiting.

That's why I think something wrong in your case.
 
IMG_1429.JPG


My score on heaven is 99.7 fps and 2513 total on the custom/extreme/ultra preset.

Seemed to be about the same as other 980ti hybrids on the web although I cannot oc it much more than +50 clock and +150 mem giving 1400Mhz speeds (that's with power allowance 110% on a separate Corsair RMX550).

I'd be interested if others are getting higher considering my 3.46GHZ processor and 24Gb 1333MHz mem.
 
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Never tested it since I don't do any heavy lifting in os. This for comparison purposes?
 
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