SLI or 1 High end Card

[insider]

My Rig is running an ASUS NVIDIA GTX760 with 2GB VRAM.
My game is giving me 50FPS atmost and I have completed 30% of the game.
So quite obviously my triangle count is going to go upwards with time, and my motherboard supports quad SLI.
So I was wondering if I could get any advise regarding upgrades.
Is it advisable to drop in another GTX760 now that their prices are slightly lower and be stuck with 2GB VRAM for the next 2-3 years.
Or
Should I get a single GTX970 and be done with it for the moment, although I don't know if it will be worth the upgrade.
I read somewhere that two GTX760s would be equivalent to a GTX Titan, myth?
And I also read cyberreality's post where his Tri-SLI GTX 980 also suffers from performance issues.
I am not aiming at playing my game on three monitors, it has to run on a single monitor at 1920 x 1080 resolution with atleast 60FPS minimum.
I don't want to be stuck with 2 GTX760's for 2-3 years but if it can outdo a GTX 970 or GTX 980 it is tempting.
Any advise would be great.

[Herb]

NVIDIA claims up to 2x performance with 2 cards, but I do think there is always overhead when 2 cards have to coordinate and pass information over a bus compared to directly executing on one chip. ie, latency increases even though GPU power increases. The other thing to keep in mind is the memory interface and memory type. GDDR5 and a large memory interface (256-bit) will have a huge impact as well (not just the chip itself).

[Kojack]

Not everything works with SLI, you may not get much performance increase, depending on the game.
Memory doesn't add either, if you have two 4GB cards you still only have 4GB (they need to duplicate the data).
SLI also has trouble with VR apparently. The 900 series has better support in theory (I think it may not be enabled yet in the drivers, not sure), they are supposed to allow each card to render one eye at the same time.

But it can also give you more speed.

I've been considering getting a laptop with SLI 980m's (to run VR stuff at work). I'm not sure though, I've never really trusted SLI.

[cybereality]

I've been running SLI for a few years now. It's not without merit, but it's also not without it's issues.

In theory you would put in a second card and get 2x the performance. In reality, this is rarely true. It depends on the game, and how optimized the driver is for that game, but you could reasonably expect around 50-60% improvement. That said, it is nearly always some boost (except in horribly optimized games like Watch_Dogs, which I'm almost afraid to install at this point). Then there are micro-stutter issues which people like to complain about. I've only seen this on occasion (with certain games) and I believe the more recent drivers reduce it significantly. In specific, I had this issue on Bioshock Infinite. The fps meter would show 200+ fps (well above the refresh of the 60Hz monitor I was using) but the animation was not smooth and would "hitch" frequently. I managed to mess with the settings, and now it doesn't happen on that game but it is unnerving a little bit.

So, in general, there are 2 reasons SLI is a good idea.

1) You need monster performance, and are already buying a top-end card (i.e. GTX 980) and one card is not enough.

2) You have an older machine and want to put a cheap, used, second card to breath some life into it.

Both cases are valid to me. However, if you have the money, you may be better off just getting a new card as a single GPU will be less headache and hassle.

[frostbyte]

I've been considering getting a laptop with SLI 980m's (to run VR stuff at work). I'm not sure though, I've never really trusted SLI.

word of warning:
i would stay away from nvidia optimus technologies...might just as well go out to the street dressed in pink and start throwing money on stray cats...

https://forums.geforce.com/default/topi ... in-fullhd/

however if you must have it...make sure you can disable from bios the intel integrated card ( only few model support this...i think alianware does...)

way optimus works, all rendering from nvidia will be redirected to the integrated gpu port so you're outputing from intel and there is nothing you can do about it...it is a flawed hardware design thing, so this problem isn't going to be fixed...

i think that being able to disable the intel gpu from bios generaly means you can output from nvidia...but i'm not sure...
any way you better check this issues more deeply before throwing money...

my lappy came with nvision capable gpu( said so on the box )...but i can't even watch 3d movies in regular 3dvision not to mention the nvision stuff...
osx86 with nvidia gpu - forget about it...linux only recently hacked its way...https://www.youtube.com/watch?v=iYWzMvlj2RQ ,now occulus community...list of injuried people just keeps getting longer and longer...
damm nvidia...

[cybereality]

Yes, I must have missed that comment on VR. If you want to do VR then a laptop is a poor choice. Nvidia Optimus has *loads* of issues, it basically doesn't work at all for VR. Some of the new 900m series can come without Optimus, so this helps but does not solve everything. In general SLI/CrossfireX is bad for VR due to increased latency (one extra frame of lag courtesy of AFR). In addition, laptops are usually too slow to get good performance at 1080P+ stereo @ 75Hz. That said, some higher-end laptops can provide some limited experience, but you may be struggling or have to turn settings down very low. If you are developing your own games, of course you can optimize for the low performance. It's just that many of the games out there now are not fully optimized (people take a normal game and just port it to VR without taking things into account) and won't run well even on moderate desktop machines.

[Kojack]

The laptop for VR is because the alternative is a imac, which is running lower spec mobile components anyway.
At home I use a full tower desktop with hand picked components. But at my college I'm surrounded with 200+ imacs with models ranging from 2010-2014. They struggle with the DK2 in anything complicated and barely handle UE4. Plus I don't have admin controls, I can't even install drivers. I need something that can run VR but I can easily move to any classroom I might be in. I'm not going to lug around a huge pc when I can get a laptop (around $4000) that should handle most of it. I'm currently using a laptop from around 2011 with geforce 485m for VR at work, it can handle it better than the pre-2014 imacs.

As for Optimus, I know it has issues. The laptop I've been planning on buying is a Clevo P375SM (my current laptop is a clevo too, I like them) which does not support Optimus. It does have dual 980m 8GB gpus and at least an i7 4810mq (could go up to an i7 4940mx if I wanted to pay more).

So my options are: keep using my 4 year old laptop, use my surface pro 2 or buy a new laptop.
But I haven't finalised my plans yet.

[Herb]

I've had enough issues with Optimus that on my Ubuntu laptop I installed the nvidia prime package that just disables the Intel chipset for everything and that fixed my issues.

The only other advantage of SLI would be use of more CUDA cores for GPU based data processing, but sounds like you what rendering power only. Sounds like 1 giant video card is the answer for you.

[cybereality]

Well if it's between a high-powered laptop or an iMac, then the laptop will be way better. As long as it doesn't have Optimus, you will probably survive.

[insider]

Thanks guys guess I ll be getting a GTX980 atlast
And no Nvidia Optimus or Optimus Prime discussion in my threads please, I am a fan of neither of them

Kudos to all

[Kojack]

And no Nvidia Optimus or Optimus Prime discussion in my threads please

What about the Optimus Maximus, the $1200+ keyboard where each key is a programmable mini colour oled screen?

[insider]

And no Nvidia Optimus or Optimus Prime discussion in my threads please

What about the Optimus Maximus, the $1200+ keyboard where each key is a programmable mini colour oled screen?

Yes you can add that to the list too

[syedhs]

And also check if the games is cpu-bounded or gpu-bounded.. so if the games is cpu-bounded, the fps may stay the same no matter how fast the card you are throwing into your rig

[insider]

And also check if the games is cpu-bounded or gpu-bounded.. so if the games is cpu-bounded, the fps may stay the same no matter how fast the card you are throwing into your rig

Yes I am already addressing the cpu-bounded issues, but I have atleast 12 high poly game objects, I just added a 300000 poly model yesterday and the frame rate got shot to 30FPS. So yes I would need a faster GPU and also optimize my game.
Edit: Hardware issue solved.

[Kojack]

The laptop for VR is because the alternative is a imac, which is running lower spec mobile components anyway.
At home I use a full tower desktop with hand picked components. But at my college I'm surrounded with 200+ imacs with models ranging from 2010-2014. They struggle with the DK2 in anything complicated and barely handle UE4. Plus I don't have admin controls, I can't even install drivers. I need something that can run VR but I can easily move to any classroom I might be in. I'm not going to lug around a huge pc when I can get a laptop (around $4000) that should handle most of it. I'm currently using a laptop from around 2011 with geforce 485m for VR at work, it can handle it better than the pre-2014 imacs.

As for Optimus, I know it has issues. The laptop I've been planning on buying is a Clevo P375SM (my current laptop is a clevo too, I like them) which does not support Optimus. It does have dual 980m 8GB gpus and at least an i7 4810mq (could go up to an i7 4940mx if I wanted to pay more).

So my options are: keep using my 4 year old laptop, use my surface pro 2 or buy a new laptop.
But I haven't finalised my plans yet.

Now that I'm back at work, and I'm now working in the office instead of at home (well, still working at home as well but not being paid for it), I need to do some purchasing.
Instead of the Clevo P375SM (sli laptop) I'm currently considering the Clevo P770ZM.
This is a single 980m 8GB (funny, why are desktop 980's only 4gb?) 17.3" laptop running a full desktop i7-4790K cpu at 4GHz. This thing should run rings around the imacs I would otherwise be on.
So no sli problems, not a mobile cpu and no optimus!

It's also got room for four hard drives (two M.2 ssd drives as sata or pcie and two regular 2.5" drives). Not sure how I'll configure that part, probably a Samsung ssd and a western digital 1TB 10000rpm velociraptor.
It's got two display ports and a hdmi, four usb3, one esata/usb3, 4 audio ports and a built in subwoofer.
Not too bad.
If I went for the 15.6" model (same specs otherwise) I could get a 4k display instead of 1080p. But 4k seems a waste on a laptop, especially at 15.6". It's also a glossy display, which I don't like (I prefer matte displays).
Of course with all that the battery life is probably measured in seconds rather than hours. But this isn't for mobile use (that's my Surface Pro 2's job), it will always be plugged in.
(I'd like to try it in a backpack for mobile VR, but it will probably catch fire. Apparently the cpu alone can reach over 100 degrees C. Blocking the fans will probably not be wise)