 A thousand watts. That is the recommended power budget for this GeForce RTX 4090 from MSI. In this economy, no wonder gamers are outraged. But what if I told you there's another way? What if I told you I'm gonna ditch my thousand watt power supply and run this top spec gaming rig complete with RTX 4090 on just a 550 watt power supply? 350 watt power supply. There will be trials. Oh crap. There will be tribulations. Ah crap. Come on. But I will be darned. Darned I say. If I'm gonna have you guys paying full price to run your rig after you, unwisely, blew your savings on a video game machine. Smart Deploy powered by pdq.com. Smart Deploy maintains drivers for you. With over 1500 driver packs to choose from, deploy any business class device with a single Windows image. Get your free licenses worth over $500 at smartdeploy.com slash Linus. So first things first, do you even need a thousand watt power supply or is this whole thing overblown? To find out, we've dusted off our Nvidia PCAT, an inline power measurement device designed for GPUs. And we've janked together a PCIeY power splitter to accommodate the four bloody eight pin PCI express connections that you need for the 12 pin adapter for this GPU. You see the PCAT was designed in the before four times when nobody ever thought you'd need more than three eight pin power connectors for a single graphics card. I wouldn't describe this as our most stable GPU ever, but I don't think it's going anywhere. There are a couple of ways that we're gonna monitor our power consumption. First of all, we've got the PCAT that I just mentioned before, tells us the GPUs power draw. Then we're gonna have a regular wall power meter, which is gonna tell us the total power draw of the system, including any losses due to the inefficiency of our power supply. We'll kick things off with a real game. In this case, Cyberpunk 2077 running at 4K, mostly high presets with array tracing set to medium. And our GPU is sucking back a whopping 430 to 470 Watts, with our total system power consumption at about 600 Watts, all while running at a cool 50 FPS. Boy, is this ever a demanding game. Almost as demanding as MSI's combustor stress testing application. Wow, it's a little lower even. I guess any additional load that combustor puts on the traditional rasterized rendering cores is more than made up for by the activation of the ray tracing cores in Cyberpunk. We're gonna need ray traced fricking stress tests. What the heck? Whatever the reason, it's pretty clear that we don't need a thousand watt power supply to run this card, which makes sense, I guess, given that Nvidia themselves only recommends an 850 watt unit for their founders edition version of the 4090, which raises the question, why is MSI asking you to spend extra money on a thousand watt power supply? If I had to guess, I'd say it's for two reasons. First, to accommodate for any extra power draw from overclocking, and second, to account for our connected peripherals, like bus powered USB devices, hard drives, LED strips. The last thing they want is for you to plug a bunch of other stuff in and then come crying to them when your system shuts down, which raises the question, how much more power could we draw in their OC mode? As advertised, system power consumption is up in the neighborhood of around 10%, but unfortunately, it didn't have the impact on FPS that I might've expected. We've gone from about 50 FPS to anywhere from 50 to 54, which kind of raises the question, has Nvidia already got the 4090 absolutely redlined? And if that is the case, could we maintain nearly the same performance, but drop our voltage for a big bump in efficiency? The first step in our journey is to drop back down to default mode, shut down the system, and try again with MSI's minimum recommended power supply, an 850 watt. Tech tip for you guys, you should never do what I'm doing where you swap out a power supply and use the same modular cables. And the reason that you shouldn't do that is because they might not actually use the same pinouts and you can accidentally fry the devices on the other end. In our case, we have painstakingly validated that these use exactly the same pinout, but we still don't recommend it. Do as I say, not as I do. Ah, no, no, just kidding, it's fine. Even within the same manufacturer, they're not always the same pinout. As expected, our performance is identical with our 850 watt power supply, as is our system power consumption at around 630 watts from the wall, meaning that it is probably safe to run pretty much any 4090 on a good quality 850 watt power supply. And that thousand watt recommendation seems to be more about butt covering than any actual concern for overcurrent protection kicking in and shutting off your computer. But if 850 watts is fine, then perhaps 750 watts is also fine. I mean, it still only says 600 watts from the wall, right? And that's accounting for the power supplies and efficiencies, sounds like 550. I think we're gonna get there. If these donuts in the middle of the intersection are anything to go by, 750 watts is fine, just fine with a hundred plus watt buffer. But that's not to say that every 750 watt power supply is gonna handle a Ryzen 7000 and a 4090. There are a couple of major factors to consider. First is transient spikes. We first noticed this with the RTX 3000 series, but power hungry GPUs like this one can momentarily draw far more power than what they are rated for. It's not for long enough to cause thermal problems like usually only for a few microseconds, but it can be enough to trigger the overcurrent protection of your power supply, especially if you're running an older unit that wasn't designed for modern beast GPUs. Another factor we're not considering here is capacitor aging. This power supply probably only has a dozen or so hours on it at most. Give it another 100,000 hours and depending on factors like how hot or cool it was running, it could be operating at maybe 95% of its brand new capacity or 90% or even much lower. By choosing a properly specced unit with plenty of headroom, you give yourself a better chance of years of trouble-free operation and help avoid catastrophic failure. Cause the thing about power supplies is when they pop, they can sometimes take everything else with them, which won't stop us from seeing how low we can go. Where's my 650 watt power supply? Lie! I don't worry, I'll get it. Now we are running into a situation where we've actually run out of eight pin power connectors coming out of our power supply. So we're going to have to employ a splitter. All the Y splitters, you know, Y splitters like, what? Sorry, Seasonic, you guys were a great sponsor. I apologize in advance for blowing up your power supply on camera. Hopefully we can work together again in the future. It's probably fine. What will probably happen is we will trigger the overcurrent protection of our power supply and the system will just shut off. We do need to drive around a bit before we say for certain, this is working. It puts a little bit more load on the GPU. I saw it at 620 there. Basically we could put a couple LED strips on this system and it could put us over the limit. For those of you wondering, by the way, we stopped using combustor because the load wasn't even as high as cyberpunk. I thought it would be higher. Oh, one thing we could do is we could put a little bit of CPU load on the system. Cyberpunk is still running in the background and what will probably happen is the game, I will die in the background and it won't actually be rendering. 567, 740. Oh, get this Brandon. How is it doing that? That doesn't seem right. Seasonic, hello? Our FPS is NA. We've left this plane of existence behind. G force experience is probably just bugs that happens sometimes, but I was, I was not expecting this. I guess it could be that their 650 watt unit is simply over spec and they set their overcurrent protection for something far in excess of 650 watts. The fan isn't even spinning. Seasonic, what you doing? I mean, that is the way to build a really high quality 650 watt power supply is if it's just a 750 watt power supply and you know, with the seven scratched out, just put a six there. Let's go lower. To be clear, I'm not expecting anything to happen at the desktop. We're sitting at like 130 Watts right now, but I am expecting something to happen because aside from going down from 650 to 550 Watts, we're also stepping down from Seasonic's prime titanium premium power supply lineup to their focus lineup, which is, I mean, it's 80 plus gold. It's still Seasonic, 10 year warranty, blah, blah, blah. But it's very unlikely that that's, you know, an 800 watt power supply and 550 watt clothing. Holy. This is not what I expected. We are drawing 630 Watts from the wall. The GPU is at 450 Watts. You know, we shot the intro for this video with the trials and the tribulation. I was expecting there to be crashes for us to cut in there. I'm gonna have to, oh, oh crap. Well, there's one. Oh, but it's okay. We have a way around it. First up in our bag of tricks, instead of turning our power target up, we are going to turn it down. Maybe 90% is enough to get by with 550 Watts. About 2,800 megahertz is what we get on this one in default. So as long as we're close to that, we are in good shape. We'll also be able to tell from the FPS the game is running at though. Oh crap. Well, we're gonna need more than a 10% power limit. How about 80? Oh, it's at 600 Watts from the wall already. Okay, come on, come on, come on, come on, come on. Ah, crap, come on. We're not defeated yet though. We found we can go as low as about 70% power limit without losing a ton of performance. Oh, I really hope we make it. 70% apply. Overall system power consumption is under 550 Watts at the wall. Crap. Crap, we couldn't even get the close up, but we aren't defeated yet. We could drop the GPU down to 60, 50% power limit. The issue is that when we do that, we risk seeing some pretty funky behavior, even if our FPS still looks okay. We might need to start attacking this from a CPU perspective. Oh crap. Oh, this is not good. Actually, before we adjust our CPU, one thing we can try is remember how I'm running a Y splitter from one of my power supply outputs to two of the inputs on our Nvidia power measurement board. Well, there's a way that we could not do that. We have four total outputs on this power supply. And what we could do is we could just run a single eight pin to the CPU and then three dedicated eight pins over to this board. I'm gonna step it back to 80% power limit. I believe we were overloading a 12 volt rail, not actually overloading the power supply. Oh God, it's at 580 already. Darn it. Brandon, you've captured plenty of the crashes so far. You don't need to have all of my failures on film. Oh crap. Oh crap. Crap, come on. I'm just gonna power straight into it. 70% power limit. Let's go. Yeah, it's still jumping up as high as like 360 watts. That doesn't seem like 70% of the power limit. God. We're not done yet. My hope is that we can save a bit of our overall system power budget by reducing the voltage to our CPU, relieving everything else on normal. We've even got PBO, Precision Boost Overdrive, still enabled, which allows the CPU to turbo up higher and for longer. But maybe by reducing the voltage, just 0.15 volts, get away with something here. We might've gone a little aggressive on that CPU undervolt, but we also really wanna see this work. So go in game, in game. Oh. We managed to drop our overall system power consumption by like 20% and all it cost us was we're running at 49 FPS right now, 48. Less than 10% of our actual real world performance. We are running a 7900X and a 4090 on a 550 watt power supply, as promised. Even though I didn't know for sure what happened. Of course, as cool as that was, nobody's gonna buy a GPU like this only to leave performance on the table. Thankfully, you can have the best of both worlds. We observed that our GPU clock was around 2.8 gigahertz under sustained load. So what we can do is go into the curve editor in MSI Afterburner, hold alt and take our very farthest dot here and drag our frequency target down to about 2.8. Then we're going to individually drag up our 950 millivolt dot to 2.8 gigahertz and apply. 2.8 gigahertz and apply. We've changed our target from 3 gigahertz to 2.8, which is fine because we were only hitting 2.8 gigahertz. Anyway, theoretically, assuming we stay stable, we should have our lower power consumption and our stock performance almost. We'll get to that in a moment. The keen eye among you will have noticed we're back to our 650 rather than our 550 watt power supply. We saw some very strange behavior with the 550. So for this demo, I just want to show you how the power consumption is low. I don't need to be using a 550 watt power supply. Game crash. Let's try 970 millivolts. And there we have it. Even though we've backed off our CPU undervolt a little bit, we're down to minus 0.1 volt and we're at 975 millivolts on our GPU, we are still like 100 watts lower than we were when we started. As for our performance, it's a touch lower, but we can fix that very easily. All we got to do is alt tab out. Then we're just going to play with our memory clock. Let's try plus 500. It's possible we could go higher than that, but 500 is pretty safe. Now we're back in game and I'm seeing as high as 60 FPS, but going back to the same area. No, it's more like, yeah, dropped under 50. Ah, let's give the memory a little more juice. Let's say 900. Still at 530, 540 watts, 52, 54, 60. I'd say we are pretty darn near we started now. Not bad for a 650 watt power supply. All of this raises the question, what if instead of going full balls out, Nvidia did what we did? We could have had smaller coolers, more sensible power supply requirements, nearly the same performance. Like in real terms, that could be hundreds of dollars in savings over the years that you might be expected to run a GPU like this. But then it's also possible that nothing would have been different. Maybe in order to get economical yields on Ada Lovelace, RTX 4000's architecture code name, they needed to accept these power hungry parts and maybe we just got a good one. The good news though, is that even if that's the case, at $1,600, this is a problem that won't affect a lot of people. And those that can afford this GPU can probably afford the running cost. Either way, it was an interesting adventure. Just like this interesting adventure into Segwayland. Ahoy, it's our sponsor. Wealthfront. Thanks Wealthfront for sponsoring this portion of today's video. Does anyone know what's going on with the economy right now? No, really though, anyone? Inflation keeps inflating and who knows if we're in a recession at the moment, but it's always a good time to save. 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If you liked this video, hit like and hit subscribe and maybe check out another video from us, the RTX 4090 review, full review we just did. If you like graphs, we got graphs.