RTX 3090 SLI - We Tried so Hard to Love It

Image from Linus Tech Tips

 On September 17th, 2020 claimed yet another victim. NVIDIA's SLI technology, which allows you to use more than one graphics card to increase your FPS in games was already on life support with lackluster support from game developers and NVIDIA slowly pulling support from more and more of their cards. But the final nail in the coffin was of course this blog post on NVIDIA's website stating that they would no longer develop SLI profiles for future cards at all or for their past cards past January of 2021.

 Curiously though, the RTX 3090 NVIDIA's latest and absolute greatest does have an NVLink connector which as of the last generation is the connector that we use for SLI, which hasn't been explicitly disabled. So theoretically, in the handful of games that do natively support it, we should be able to run SLI on this card. Raising the question of course, given how CPU bottlenecked this is on any kind of mere mortal monitor will a second RTX 3090 even make any difference? I legitimately don't know. 

I have intentionally cloistered myself and not looked at anyone else's videos on the subject. Just like I haven't looked at who's our sponsor. There it is. Ridge Wallet. Ridge Wallet wants to redefine the wallet with its compact frame and RFID blocking plates. Check out how they can keep your wallet bulge down and use the offer code "Linus" to save 10% and get free worldwide shipping. (upbeat intro music) As much as I would have loved to throw two of NVIDIA's changes founder's edition RTX 3090s in here and see just how well this through card blowy thing works when you've got two of them stacked on top of each other. 

I wasn't able to get another one of those. So we're going with an Asus'sROG Strix gaming RTX 3090. Now I don't know much about this card other than that Asus did manage to dodge the whole fiasco with bad board components causing crashes and stuff like that. So, good job Asus, you did well. She's a heavy boy for sure. So we've got three fan configurations with the counter flow. So that's that this one has spinning clockwise, the others are spinning counterclockwise something, something turbulence. We do, oh, that's interesting, we do have a little bit through the card blowies here. Sort of it's a much more traditionally shaped PCB but the cooler extends for a that looks like a good couple of inches past the edge of the card. 

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Now you might've noticed I didn't take the plastic peels off this one. That's 'cause this one gotta go back to Asus. Funny story, they were like, "Hey, be real careful with that one because it's the only one we have and we to do some stuff with it." You know the product is in shortage when even the manufacturer does not have any. Fun fact about our system configuration here the MSI Z490 GODLIKE was the only motherboard in our studio that was capable of handling this configuration. Not because we didn't have any other boards with four slots spacing slot spacing, which is what we need, at least to have any room for the top card to breathe, but because it was the only Intel-based one that had that.

 And trust me, I love Ryzenas much as anyone does at this point, but if you're running two RTX 3090s, you are going to need the fastest possible gaming CPU which for now anyway is the 10900K. This is fricking nuts. Like, look at this. The whole bottom of the case is full of graphics. I love that these fans are going to be blowing right into this bottom card. This one, good shape for cooling. This one, well might be okay. It's not the best case for this, but we're just gonna leave it open. So it gets enough airflow. Hey, we might have a slight problem. 

- [Alex] Yeah? Oh yeah. - We got four eight-pin connectors and that's not enough today. Each of these needs three eight-pin PCI express connectors that have gotten to be overkill. - [Alex] Do you think the power supply will be good enough? - What's in here? - [Alex] 1000 watts Seasonic. - I have my doubts. - [Alex] It was able to run four GV-100s for months. - Yeah, I still have my doubts. Cable me. - [Alex] Nice catch. - This is NVIDIA's NVLink bridge with four slots for 30 series products. Yes my friend NVIDIA, friend. 

Yeah, I guess I don't have friends plural anyway. Yes, my friend, NVIDIA has changed the NVLink connector again. So it's OneCard, one NVLink connector. This one is keyed differently and has I think double the bandwidth over the last one? - [Alex] Maybe.- [Nick] Yes. So wait, at what point did NVLink replace SLI in terms of branding? - It didn't. SLI was and continues to be the branding for multiple cards working together for gaming. NVLink is just the name of this communication protocol and connector, which happens to be much much faster than the original SLI finger and even the high bandwidth bridges that NVIDIA introduced later on. 

The reason it was developed was not for gaming, it was actually for their like AI and like data center products but, if they were gonna build this high speed interconnect you might l put it on the gaming cards as well. Is what I'm assuming the thinking was. NVLink is so much faster than the SLI interface was that it can even allow their other cards to pool their memory together and work on much bigger jobs. We talked about this in more detail in this video right here. Aight, please tell me it's just gonna boot up. Wow. That is a very sharp RGB. And NVIDIA control panel, dual 4090s, they show up, SLI boom. There it is. It may be dead, but here's it's a shambling corpse. 

With that out of the way, let's have a look at the wide selection of SLI ready games that we can enjoy. Shadow of the TombRaider, Civilization VI, Sniper Elite 4, Gears of War 4, Ashes of the Singularity: Escalation, Strange Brigade, Rise of the Tomb Raider, Zombie Army 4: Dead War, Hitman, Deus Ex: Mankind Divided, Battlefield 1, Halo Wars. Oh, that's all the DirectX 12 ones. Also in here are some Vulcan games with support, including Red Dead Redemption 2, Quake 2 RTX, Ashes of the Singularity: Escalation, Strange Brigade, and Zombie Army 4: Dead War. Dang, it. Three of those are from the other list. 

They just support multiple APIs. So installed on this system, we have almost every SLI capable game. That is pretty rough looking. Where do you wanna start? Should we go straight for one of my favorites, Shadow the Tomb Raider? Sure. But when we go for it, we are going for it. I'm talking 4k maxed everything except motion blur, (beep) motion blur. - [Alex] Yeah. There's a thing on the forum the other day talking about how people donat think that you should hate motion blur so much. - Really? - [Alex] Yeah, I don't get it. - Wow. They are both at 90 plus percent. That's pretty cool. 

So did you, can, you know what? No, I don't wanna run the benchmark yet. Can I just enjoy it for a little bit? - [Alex] Yeah. - This is the kind of gaming setup that even 10 years from now, most people will have never experienced. So I wanna at least try it out. That was some interesting flicker right there. (Alex laughs) You piece (beep) you knew that was gonna happen, didn't you? - [Alex] Yeah (laughs). - That was so anticlimactic Look how funny he thinks he is. - I even have it all set up. - No, don't go away. You're helping me plug this in. I probably should've seen that coming. 

Something to note is that while 1000 watts is probably enough to realistically power these cards under a sustained load, what's interesting about the RTX 30 series is that it can experience sudden spikes in current that can trip the overcurrent protection of a power supply that on paper, seems like it should be able to handle the load. So for years, NVIDIA and AMD both had been recommending power supplies that I would look at and I'd, "Ah, you can get away with less than that." But for the first time would say, you should probably go 20%over their recommendation to make sure that you don't experience something like that. 

All right, let's try this again. And this game maxed out. Looks freaking incredible. What's more surprising to me is the usage of these GPUs. Both of them are above 80% usage. That's crazy. You can hear'em ramping up already. Even at our lowest DPS, we're not seeing any lower than 50 to 55 frames per second, which especially on a G-sync monitor, is gonna feel fluid. Not quite as fluid as if you just had one GPU doing it though. This is interesting and well, part of why SLI is dead now. Now to measure a little more objectively we're gonna let frame view run for 180 seconds while The Shadow of the Tomb Raider benchmark runs its course here. And apparently, I'll go have a quick meeting with Nick light about our merch stuff, lttstore.com. Look at this over therewith the Razor mask, - Hey what's up?

 - Hiding in the shadows - Hey. And the shadow of the Tomb Raider. - [Nick] They call me shady guy. Before the benchmark's done actually, we've got a really good opportunity to check out our max power draw here. 'Cause Shadow of The TombRaider is consuming anywhere from 85 and 100% of the GPUS all the way to like 90 and 100%. So I did say before a thousand watt was probably enough and it probably is. Remember that the power supply isn't quite 100% efficient, even if it's 80 plus platinum or titanium, and this is drawn from the wall. So realistically it's gonna be somewhere in the 950-watt range right now. That's right. There's finally a system that needs a 1000 watt power supply and more for the spikes, you know. Crazy. 

Alex hasn't even finished transcribing the numbers and I can already see the problem. While our 90th percentile and 95th percentile numbers are way higher than a single GPU, it all falls apart in the 99th percentile. So what that means is that90% of the time, SLI is damn near 70% faster than a single card. But 90% of the time, isn't what you feel when you're playing. 1% of the time, it dips down just as low, which is exactly those little stutters that I was feeling when I was playing. - [Alex] Yeah there's the graph. - Here's a graph for the- Whatever we'll overlay it. Here's a graph, you guys saw the graph already. Next game. It's always interesting to see how game canned benchmarks can disagree with Nvidia's frame view tool. This says 86 FPS minimum, that sounds pretty good. Frame view says 94. Wait? - [Alex] Yeah. Oh wow, well that's great. Deus Ex: Mankind Divided, if you're still playing this game, SLI RTX 3090 looking like a pretty good option. While we fire up Red Dead Redemption, let's take a moment to appreciate the aura coming off of this machine. So here, we should move your laptop. It's going to get booked Alex, it's gonna get cooked. - [Alex] Oh, should I get the FLIR? - 

Yes. Before we get the thermal camera though I just wanna show you guys where I can feel the heat of this machine from. Holy crap, I think I can still feel it. Here 100%. I mean, it's a thousand watts. It's like having a space heater on your table. I should have half expected the next result to balance out that good one. Red Dead Redemption 2, just won't get past this black screen trying to load the game. So, so much for 15% of the supported games list. - [Nick] Yeah. - To be clear there might be some way to get it working but we're not gonna spend any more time than that and neither should you. 

This is a short benchmark apparently, 30 seconds. Hard to read frame view with the in-game stats all up in my business. I just wanna see how much usage there is. Okay. The good news is it's working. The bad news is I still can't see how many GPUs. But that's okay. 'Cause, we brought the thermal camera. Wow, that top card is running a little hotter than the bottom one. 48.6 there got a cool 65 on the top. Dang. All right, summary time.

 That confirms what we thought we knew. SLI did nothing, it made it worse. Yay SLI. What's next? - [Nick] That's all of our pre-done benchmarks. - That's as far as we got, honestly, I'm good with that. None of these other ones, you know what? Let's just play Quake 2 RTX for fun then. What do you think? The most overkill Quake2 machine of all time. It's so warm. All right. So we've got eight freaking reflections. How has our GPU usage? Not bad. GPU two sitting at about 80%here, ladies and gentlemen. That's pretty cool. Please die please die. Is he dead? I can't tell. He dead. Okay, here we go. Oh, come on. I'm down to like 19 health. I'm just gonna, I'm running for it. I'm running for it here boys. I'm running for it, we're going, we're going- Get out of the way. All right, forget it. I'm out. But you should do the heat test, you should do the heat test. I can feel it from here. 

Like easily, like flip your hands around now. - K yeah. - Yeah, that's what I thought. - [Nick] How much is drawing just in Quake right now? - Let's have a look. It's still maxed out at 1022. In a quake, it's sitting at... I'm gonna assume it's lower than Shadow of the Tomb Raider. I suspect it's not doing much on CPU. 908 Watts. - [Alex] That's quite a bit. Do you know what else is quite a bit? Your patience with my Segways to our sponsors. Micro Center is open to supply all of your technology needs whether your work from home or learn from home. Check out their power spec, a desktop lineup featuring Intel 10thgen processors available in a wide variety of configurations, including NVIDIA RTX graphics and anywhere from 16 to 32 gigs of RAM.