Due to the fact that most modern games rely heavily on GPUs in order to run properly, gamers must have a powerful graphics card in their system if they want to be able to run their favorite games on higher settings.
And, if you want to max out today’s top games at higher resolutions (1440P, 4K, and beyond), even more graphics processing power is required.
While the ideal solution to handle more demanding games at higher resolutions (and higher refresh rates) is always just to grab the best graphics card available (right now that’s a GTX 1080 Ti), there is the option for some (especially those with unlimited budgets) to utilize multiple graphics cards in the same setup in order to try and get even more performance out of their systems.
Both NVIDIA and AMD GPUs offer technology (SLI and CrossFire) that allows 2-4 of their graphics cards to work together in a single system to help deliver more GPU power. But, is running multiple GPUs in SLI or CrossFire configuration an option that is worth considering?
In this article, we’re going to break down how SLI and CrossFire work and how they’re different, as well as discuss what some of the pitfalls are that come with running multiple graphics cards.
SLI vs CrossFire: A Primer on How They Work and the Differences Between Them
Both SLI and CrossFire accomplish the same thing: they allow a system to split the load of processing graphics-related data between multiple graphics cards.
Theoretically, having multiple graphics cards split up the workload of processing frames means that your system can render frames more quickly, but as you’ll see further down in this post, multi-GPU configurations don’t offer a linear scaling of performance (although, in certain games, dual GPUs can produce a near doubling of performance in terms of average framerate).
But, before we get into some of the pitfalls of multi-GPU configurations, let’s discuss the differences between SLI and CrossFire.
First, SLI is NVIDIA’s multi-GPU solution whereas CrossFire is AMD’s multi-GPU solution. Again, both are similar technologies in that they both allow you to utilize multi-graphics cards in the same system.
Both technologies also operate in two different modes:
- Split frame rendering: Essentially, the GPUs split up the workload of processing each frame. So, one GPU will work on one “portion” of the frame and the other GPU will work on the remaining portion
- Alternate frame rendering:Â The GPUs split up the workload by working on alternate frames. GPU 1 will handle frames 1,3,5… and so on, and GPU 2 will handle frames 2,4,6…
However, there are a couple of main differences to be aware of:
- SLI requires you to use identical GPUs (so a GTX 1080 can only be SLI’d with another GTX 1080—although, the brand of the card doesn’t matter), whereas CrossFire will work with different GPUs of the same architecture (an RX 580 can be CrossFired with an RX 570, but not with an R9 390)
- SLI requires that the two cards be connected with a cable or SLI bridge. AMD cards used to require that the multiple cards be connected, but in updated versions, AMD GPUs in CrossFire configuration now just communicate via PCIe 3.0
- SLI configurations are generally more expensive than CrossFire configurations because NVIDIA requires motherboard manufacturers to pay to be “SLI” certified, whereas AMD doesn’t require any kind of certification and, as a result, there are lot more motherboards—including budget-friendly options—that support CrossFire.
The Pitfalls of Using Multiple Graphics Cards
While utilizing multiple graphics cards has been a great way to help users get more in-game performance out of their systems, in recent years, the performance advantage of running SLI or CrossFire systems has diminished slightly.
In the past, more game developers took the time to develop their games to be compatible with multi-GPU technology. Nowadays, though, fewer developers are working to optimize their games for SLI and CrossFire configurations.
Still, though, running dual GPUs can provide a nice increase, with many benchmarks showing ~50% higher improvements when adding a second card.
Questions do surround the future of dual-GPU setups, though. NVIDIA themselves have even pulled back on SLI support on a few of their latest generation cards. Only the GTX 1070 or higher can be SLId. The GTX 1060 can technically be set up in multi-GPU configurations, but it is not officially supported by NVIDIA (they have not included the SLI connection ports on 1060s).
Another downside of running SLI or CrossFire setups is the costs involved make them a tough buy for anyone that has any kind of restrictions on their budget.
While one could argue that since dual GTX 1070s cost only slightly more than a single GTX 1080 Ti and often outperform a single 1080 Ti in benchmarks, that they offer a similar (or better) price-to-performance. However, the reality is that dual GTX 1070s will require you to spend more money on your power supply, motherboard, and your case/cooling. This is because dual graphics cards will produce more power consumption and heat, and will also require an SLI certified motherboard (which are typically more expensive) as well.
So, you have to factor in those extra costs when determining the price-to-performance of running multiple cards.
So, When Do Multi-GPU Configurations Make Sense, Then?
The main reason why SLI and CrossFire exist it to help users get more performance in scenarios where even the most powerful single GPU setup won’t cut it.
So, nowadays, that means scenarios like trying to run games at max settings on a 1440P 144Hz (or higher) monitor with 144FPS. Or, trying to run games on a triple 4K monitor setup. Or, really any other extreme scenarios along those lines.
While graphics cards like the GTX 1080 Ti and GTX 1080 do perform well in 4K gaming and can handle most games on higher settings on a 1440P 144Hz monitor, the reality is that they still aren’t quite enough in some of those extreme use cases.
And, that, really, is where multi-GPU configurations come into play. No, they won’t give double (at least, across the board), or triple, or quadruple the performance boost over running the same card on its own. However, if you’re looking to build a gaming computer so that you can play games on as high of settings possible, with as high of a framerate as possible (especially on a 4K or 1440P 144Hz monitor), then you’re probably working with a very high budget anyways. And, in that case, you can probably also afford to drop the extra money on a second (or third, or fourth) graphics card in order to squeeze out as much performance for those scenarios as possible.
The other instance where it makes sense to utilize a multi-GPU setup is when you have an older generation graphics card and it would offer you better price-to-performance to add a second card, rather than upgrading the old card to a higher-end single GPU.
For instance, if you have a GTX 970 and you’re looking to get more in-game performance out of your system, you might be better off picking up a second GTX 970 for about $175 (used) on eBay and that should give you a decent performance boost in the games that utilize SLI properly. On the flip side of that, you’d have to pay at least $400 currently in order to replace the GTX 970 with only a GTX 1070—which isn’t that significant of an upgrade when you consider that the GTX 970 is still a fairly new GPU.
Ultimately, if you are looking to build an extreme gaming computer so that you can push games at max settings with as high of a framerate as possible on higher resolution monitors with faster refresh rates, then going with multi-GPUs is an option you’ll want to consider.
Are SLI or CrossFire Right for You?
In this post, we’ve outlined what SLI and CrossFire are, as well as broken down how they work, what scenarios they make the most sense in, and what the potential pitfalls are in running them.
For most users, SLI and CrossFire don’t make a ton of sense. If you’re gaming on a 1080P or standard 1440P monitor, running multiple graphics cards probably isn’t worth it. If, however, you’re trying to max games out on a 4K monitor or a 1440P 144Hz monitor, adding a second GPU might help you handle those more extreme scenarios.
Hi there,
I’ve been trying my hardest to find the most optimum graphics set for a GA-Z87X-UD4H (rev. 1.x).
I’ve not looked at PC technology for the past 7 or 8 years, now completely lost in the amount of new technology and setups.
Any help would very much appreciated, please anyone?
Thank you.
Apologies for the missing words. 😆
I am still confused
i have built an all AMD system in February this year, my system is a ryzen 5 3600x with two Powercolor RX 580’s in Xfire. It all looks good in artificial benchmarks. Problem is none of the newer games will work with it, Ark crashes to the desktop in AFR mode, and just freezes in 1×1 mode. DOOM isn’t working with xfire either, neither does halo:MCC. nor does Call of the Wild. Flight Simulater 2020 crashes also, there is just no longer and developer support for this technology, at least I can’t get it to work. i got both these cards for less than one GTX1060, but what’s the point in this generation?
(It should be noted that Ark crashes if you play for over an hour, play for under an hour, look at it sideways, equip any weapon more deadly than a club, et. al.)
Im really curious about this because i am running the same set up as you. or well thats what im here to decide. im also running the ryzen 5 3600 with just a single rx580. is it worth it to invest in a second gpu ? power is not an issue. and neither is air/cooling. have you played any games where you noticed a large improvement from before?
Amazing article, very in-dpeth articel that helps us choose between these two.
Thank you for the informative post.
I’m quite curious about this but since im using 1440p monitor, so I dont think its worth it.
To sum up – coherent, concise and well written.
No plugs, no green vs red team rubbish. I wish more tech writers would follow this style of writing.
I’m subscribing to your channel. My first tech subscription.
My thanks and gratitude.
What about NVLINK? Any discussion on this for 2020?
i want build a high end gamming computer i want name it the monster cpu i will make it for game shop , u have unlimited budget to make it , can i put 4 gpus 2080 ti in sli mood or what and what is prossesor amd thridribber with 64 core and 128 thrid or intel 9900 ?
what u think i do to make the monster of gsmming pc
So I recently upgraded to 1440p, 1070 ti wasn’t quite cutting it. Picked up another 1070 ti for 200 bucks now running in SLI. So I technically can out perform a 2070 in most games that I typically play for less than half the cost of a 2070 ($550+) So i think this is more of the only kind of practical application for SLI. Buying two new cards for SLI is dumb, but buying one years later for pennies on the dollar of what you paid for the first one for a 30% bump is pretty solid.
Im thinking of doing this too with my Zotac gtx 1070 amp extreme, 1440p monitor.
Have you encountered problems gaming in sli?
As an end user of SLI for going on 5 years now (then CF prior to that for 7 years), I can tell you that getting into SLI passed 2017 is a huge mistake. Why? SLI coding has to be tested and implemented in a game’s engine for it to be used. Most gamers and development teams don’t utilize it, especially now.
I’m saying this having spent countless hours attempting to find a SLI compatibility profile with NVInspector for many, many games only to be discouraged by poor graphical glitches if I did get it to work for higher rendering. Most of the time you’ll wind up with much lower framerates or zero improvement and a lot of frustrated steps earned along the way.
I can not speak in regards to NVLink as that is an entirely different beast (despite what Google results will tell you). Or CF with AMD’s Navi architecture (DX12/Vulkan APIs only). These technologies have yet to be fully tested, but show promising results. However, the problem here lies again with the development team for the game coding for it, and as I said before, most end users do not have mult-GPU configurations, so most developers won’t code for it.
I’d highly advise to avoid it and just upgrade your 1070 to a single, more powerful GPU.
Thankyou , this is enlightment.. i am playin in 1080p and cheap ultrawide monitor
Great review,appreciated and timely.
Brent,
Thank you for the explanation of SLI and CROSSFIRE GPU. Single card for my DCS Flight Sims at 1080p works great. Again… thank you.
Wow. It is clearly obvious why neither AMD or Nvidia want us running crossfire or SLI. Though Nvidia have taken the more logical approach. Running older cards in dual card format is often way better than running a single new expensive card at reduced cost. Don’t believe me, check out Game Debate. I currently run 2 x RX 290 and it is difficult to beat without spending a lot of money on a single card. I am currently upgrading to 2 x 580 4 gb Asus Dual for a cost of around £250. Compare that set up to a £400 5700Xt and my rig is 5% better. better @1080 and pretty much on a par at 1440, It is only at 4k that the 5700 come out on top. For me not worth the extra. My asus cards are actually factory oc so should do even better, To match the performance of my rig with a single Nvidia card is way to expensive. Now look at Vega 64 in Crossfire and the vega rig is significantly better at all resolutions. Amd have twigged! Savvy buyers are buying older cards, often used cards for crossfire rigs that beat their latest offerings at a fraction of the cost. Hence they are trying to phase crossfire out but it will be years before they bring out a card that will defeat a vega 64 crossfire rig at a decent price. Nvidia are way more expensive and again to beat the amd 64 rig you have to spend a ton of cash on a single card or go SLI with cheaper ones. (Which are still expensive because Nvidia are more expensive), This is why Nvidia are only now supporting high end graphics cards for Crossfire because they don’t want you pairing 2 x 1070, which is on a par with a 2080 Ti. Nvidia solution though simply pushes the time frame, and won’t stop people buying 2 older cards, even used one to run SLI as it costs a load less than there performance equal single cards.
For the Gamers, encourage SLI and Crossfire. It’s the best thing that ever happened to the gaming market.
This is very true. I’m running CrossfireX with 2 Sapphire 390X 8GB Nitro’s and they run crossfire with no problem @ all and the cards are old but still beautiful looking and powerful together. Glad I invested in crossfire or I’d be screwed in today’s times with the low availability of GPUs and their prices.
Ok then… sat here wondering what you play exactly. Or is it more like an ornamental piece?
Dear Brent,
You are literally the only reason I am passing my high school cyber class. I am learning more from you than from my online course. Thank you! :^)
I think SLI and Crossfire will not survive much time. Btw the information you gave was great
SLI and Crossfire are not supported with DX12, Mantle or Vulkan. However, Explicit Multi Adaptor is. EMA uses all GPU core assets available to the API even mixing AMD and nVidia branded GPU on the motherboard.
However as in most technology, Game Developers optimize for it a given the state of barely competent coding by developers now that would seem to be unlikely. WHen one considers that a single GPU add-in boards today far exceeds the capability of GPU AIB during the heyday of SLI and Crossfire; multi-gpu’s for gaming are simply not necessary.
Having said that, there are those folks who want performance at all costs, and if you are running CUDA or OpenCL code or even code for animation or rendering or engineering modeling then multi GPU’s could likely be cost effective.
For gaming? Multi-gpu’s will give you no edge!
Thank you for the synopsis… for gaming ? no edge.
Hi. I just read your article on sli. Here’s my take. November, 2018, I upgraded my original never-oc’d i2500K to i5-8600 non K. An MSI 370 sli+ mobo, 750 W psu, 16 gb ram. I bought new, the gtx 970 and it’s always been great. So when I just upgraded, I did some reading and the cost of another 970 as opposed to a new gpu wasn’t worth the money, so I found an exact 970 and now do the sli thing. I’m watching a lot of youtube videos that compare gpu’s while playig certain games to see what they look like today, in Feb. 2019. I’ve never had a problem playing any game at max settings. I’m not playing Metro Exodus and Far Cry New Dawn. The sli is outstanding in Far Cry, and Shadow OTTR. I’m still trying to figure out how it is with Metro Exodus. I’ve only had it a week. I think I had some stuttering stuff on Ultra, but I’m also reading that gamers with great rigs are having this problem. I’m reading that there are issues with Metro Exodus with various users. To the contrary, I was watching a guy on youtube playing Exodus with the i3-8300 and RTX 2060. He had great numbers. On youtube, I see a lot of games and gpu’s and my sli keeps up with even the 1070’s and it even beats the new 2060.
My debate with myself now is this; is it time for a new gpu? With my numbers, I think not yet, but when I relate it to my i5-2500 K, it was time, so is it time now? I’m also thinking that maybe it’s just me, wanting a new rtx 2060, or maybe the new gtx 1660ti. I plan to never go i7 or any i5 K model because I love the low temps of the i5-8600. Even now, my 8600 plays 50-55 C and the 1 gtx 970 runs in low to mid 70’s and the other 970 runs in the 60’s on sli supported games. According to Afterburner, I’m getting great fps in SOTTR and Far Cry and even over 60 in Exodus. I have set the Afterburner to keep my 970’s to max at 70 C. I hope that this is good since I’m new to this clocking thing, but I found that one of my gpu’s was high 70’s if I left it untouched.
If I read “GAME DEBATE” correctly, here; https://www.game-debate.com/gpu/index.php?gid=4051&gid2=2868&compare=geforce-gtx-2060-5gb-vs-geforce-gtx-970-msi-gaming-4gb-edition-sli I’m doing better than the rtx 2060. So going by all this, I should keep my sli running with my 8600. I should say that I never play on-line, multi-player games, only solo campaigns and only 1st person shooters. No kung-fu type games, only shooting bad guys and zombies. I forgot to mention, that since I do play solo, I use , because I like to have all the toys, so when I’m having a little trouble now in Exodus, I’m trying to figure out if it’s the game with my sli 970 or is it the that’s causing some issues. I will say that I haven’t had any issues when I turned the settings to . I can’t even tell the difference between Ultra, high, medium and low. It all looks the same to me.
I do apologize for running on so long but I would like your input, if you read this. Also, I’d love your opinion on if I should spend and buy the gtx 1660ti or rtx 2060, to be “in the game” for the new games that come out every year. And is it worth it to buy into this “ray tracing” thing, which I know nothing about and is it even needed. That’s why I like this 1660 ti gpu. I can’t find any information on newer gpu’s coming out soon, so maybe the 1660 ti is the last for a while?
Thanks again. I hope to read what you or anybody thinks I should do. Paca
Ray Tracing is something of another LEVEL. The Gaming experience of those who have played Battlefield V or Shadow OTTR or other games, only they can explain it. I was just awestruck. I’m pretty sure that anyone who buys a RTX enabled card, won’t be disappointed.