7 Best CPUs for RTX 3090 PC Builds

With the launch of the new Ampere-powered RTX 3000 series of graphics cards, Nvidia included the mighty RTX 3090, an enthusiast-grade GPU, which is an absolute monster. With over 10,000 CUDA cores, 24GB of GDDR6X memory, and PCIe 4.0 support, Nvidia shows us what they can truly achieve. Therefore, you’re definitely going to want the best CPU for RTX 3090 in your systems to take full advantage of what this GPU has to offer. Anything less than that will probably create a bottleneck and prevent us from enjoying all the power and features the RTX 3090 comes with. Powerful graphics cards require powerful computer processors, and there are only a few of them that are up to the task.

While most of the attention is the RTX 3080, which is also impressive and quite more affordable, the 3090 deserves a great deal of respect for the sheer amount of power it provides and the future possibilities it unlocks. It’s more than your typical high resolution or VR gaming GPU. The RTX 3090 is becoming one of the top choices for a variety of workstations as well. Therefore, we’re going to explore a list of CPUs that are at the top of their class, both for gaming as well as highly demanding productivity tasks. But keep in mind that there are a couple of budget-oriented processors that will manage to keep the RTX 3090 in check, even though this GPU is aimed towards the high-end PC market.

To summarize the RTX 3090, it’s roughly 20% more powerful than the RTX 3080 if we compare the technical specifications, has more than double the amount memory, and it’s the most power-hungry GPU on the market with a requirement of 350W. With that in mind, you should check your power supply and make sure it’s a beefy one because you’ll need all the power you can get.

Best CPUs for RTX 3090 Builds

The RTX 3090 is aimed towards 4k and even 8k gaming, but the impressive 24 GB of memory is more aimed towards intensive workload tasks. So let’s see which CPU can fit in and fully unlock Nvidia’s behemoth.

1AMD Ryzen 9 3950X

Architecture: Zen 2 | Socket: AM4 | Cores/Threads: 16 / 32 | Base Frequency: 3.5 GHz | Top Boost Frequency: 4.70 GHz | TDP: 105W

Key Features:

  • 16 cores
  • PCIe 4.0 support
  • 7nm technology
  • 72MB GameCache memory
  • Supports up to 128 GB DDR4 3200 MHz

Not so long ago any CPU with more than 12 cores was found only in the “enthusiast” bracket for a premium price. AMD has successfully blurred the line between high end and budget by offering a high powered 16-core CPU at an affordable rate. The Ryzen 9 3950X is a workhorse that can be pushed to 4,70 GHz and comes with next-gen 24 PCIe 4.0 lanes. These factors alone make this processor an excellent choice for a future-proof PC built around the RTX 3090.

Furthermore, the 3950X requires a motherboard with an AM4 socket, just like many other AMD processors. If you already have a PC equipped with an older Ryzen CPU, chances are you already have a compatible motherboard to go with the 3950X. However, keep in mind that if you want to take advantage of the fast PCIe 4.0 lanes, you’ll need a motherboard that supports the interface. That means an x570 model is needed. Otherwise, PCIe 3.0 will be used instead and the processor won’t operate at maximum efficiency. AMD has designed its algorithms to take full advantage of the speed boost provided by the next-gen interface.

With an impressive 72MB of total GameCache memory (L1 + L2 + L3), as AMD calls it, this Ryzen 9 is indeed fast, even when operating at stock clock speeds. However, this characteristic comes with a downside for those that want to take full advantage of the CPU. To overclock it and run it at 4,70 GHz we need a serious cooling system. AMD recommends a good quality water cooler to tame the 3950X, but a 280mm air cooler should be able to keep the temperature under control. Anything less than that just won’t cut it.

All in all, the Ryzen 9 3950X is a high-speed, overclockable 16-core CPU that will allow you to extract every ounce of performance out of the RTX 3090. Just make sure you can keep the heating under control.

2AMD Ryzen 9 3900X

Architecture: Zen 2 | Socket: AM4 | Cores/Threads: 12 / 24 | Base Frequency: 3.8GHz | Top Boost Frequency: 4.6GHz | TDP: 105W

Key Features:

  • PCIe 4.0 support
  • 7nm technology
  • 70MB GameCache memory
  • Supports DDR4 3200 MHz
  • Wraith Prism Cooler included

The 3900X is the mainstream version of the aforementioned 3950X, bringing a lot of power per dollar despite four fewer cores. Thanks to AMD’s 7nm process, the cache is massive, providing much higher speeds than 14nm CPUs at lower prices.

While also including PCIe 4.0 support, this CPU comes with all the features we see in its slightly more powerful cousin, the 3950X. However, compared to other processors on the market, there’s not as much overclocking room. The maximum speed might be more than enough in most situations, but who knows what the future brings. This is why future-proofing your PC is important, and those who would purchase a top of the line piece of hardware like the RTX 3090 should certainly pay attention to this aspect. But again, this depends on the intended use. A CPU overclocked at 4.6 GHz or close to that value should be more than enough for a premium high-end gaming system. It’s certainly enough to handle Nvidia’s newest beast.

The Ryzen 9 3900X also comes with AMD’s Wraith Prism air cooler, which is quite good and can easily keep the processor at low enough temperatures. It can even handle some overclocking, but if you want to squeeze every last MHz of clock speed, you’ll need an aftermarket cooler.

In conclusion, get the 3900X if the RTX 3090 did enough damage to your pocket. It’s a powerful processor and will handle any game at 4k resolutions, at least for now.

3Intel i9-10900K

Architecture: Comet Lake-S | Socket: LGA 1200 | Cores/Threads: 10 / 20 | Base Frequency: 3.7GHz | Top Boost Frequency: 5.30GHz | TDP: 125W

Key Features:

  • 10 cores in the affordable range
  • Thermal Velocity Boost technology for high overclocking
  • New overclocking controls
  • Hyper-Threading technology

While Intel continues to push their 14nm CPUs to new heights, they managed to boost the i9-10900K to an impressive 5.3GHz clock speed. This is all thanks to the new Thermal Velocity Boost technology that gives the cores additional power in controlled bursts. But even without using this new feature, the CPU can reach a regular overclocked speed of 4.9GHz, which is still impressive.

Unfortunately, with such high clock speeds, a system that combines this i9 with the RTX 3090 is going to need a serious amount of cooling, as well as a powerful power source. In addition to the 350W requirement of Nvidia’s GPU, the i9 requires 125W. However, when the processor is pushed to its limit, it’s going to need a lot more juice than that. If both energy and heat are kept well under control, we gain 10 cores of tremendous power. And even if that doesn’t sound as impressive as 16 cores or more, few if any games can take full advantage of anything beyond 12 cores. So having 10 cores capable of running at such high clock speeds is certainly no impairment for a system running the infamous RTX 3090.

The more important downside of using this processor is the fact that it doesn’t have PCIe 4.0 support like the Zen 2 line of Ryzen CPUs. This translates to slower reading speeds as more and more graphics cards are becoming PCIe 4.0-ready. Keep that in mind when you consider the future-proofing side of PC-building.

4AMD Ryzen Threadripper 3970X

Architecture: Zen 2 | Socket: sTRX4| Cores/Threads: 32 / 64 | Base Frequency: 3.7GHz | Top Boost Frequency: 4.5GHz | TDP: 280W

Key Features:

  • 32 core-processor
  • A whopping count of 88 PCIe 4.0 lanes
  • 7nm technology
  • 144 MB GameCache memory
  • Quad-channel DDR4 support up to 3200 MHz

Do you want to render, encode, develop, stream, and game at the same time? Then look no further than the Threadripper 3970X. This 32-core unit is built for heavy workloads and it will cut a lot of your wasted rendering time and other complex processes. It’s not designed for typical PC gaming builds and the price certainly demonstrates that. But what else would you want to be paired with a top of the line GPU like the RTX 3090?

Every specification we look at is simply mind-blowing. It comes with an out of this world total cache of 144MB, 88 PCIe 4.0 lanes, quad-channel DDR4 support, and we can even get 4.5 GHz out of 32 cores. That’s a lot of cores and a lot of power. Unfortunately, that also translates to a high electricity bill. The Threadripper requires 280W of power! That’s a lot when compared to a 105W Ryzen 9. Combined with the RTX 3090’s power requirements we can conclude that we’ll need only the best PSUs on the market and a cooling system that matches. This kind of build simply can’t be restricted by budget.

The main strength of this processor is its ability to multitask at high speeds, so remember that when you’re considering spending roughly $2,000 on a CPU alone. And that’s not all. To install the Threadripper we need a TRX40 motherboard that’s equally high-end as well as expensive.

5AMD Ryzen 7 3800X

Architecture: Zen 2 | Socket: AM4 | Cores/Threads: 8 / 16 | Base Frequency: 3.9 GHz | Top Boost Frequency: 4.50 GHz | TDP: 105W

Key Features:

  • PCIe 4.0 support
  • 7nm technology
  • 36MB total GameCache memory
  • Wraith Prism cooler included

A high-end processor is always a good choice, especially when it comes to the RTX 3090, but it’s not the only option. There are few consumer-grade CPUs that enable us to get the most out of this graphics card. The Ryzen 7 3800X processor is one of them.

The 3800X is an 8-core CPU that offers a good mix of single- as well as multi-threaded performance. Its clock speed is particularly great when considering its price. In fact, as a non-overclocked processor, the 3.9 GHz base frequency is higher than what we see in other products in its price range. This makes it a good choice for the average user that doesn’t like overclocking. But chances are that those who invest in an RTX 3090 are not going to run their CPU at base clock speeds. Fortunately, the boosted frequency is also good enough to satisfy 4k gamers and it will not cause any bottlenecks.

The Ryzen 7 3800X also features the same technology as the more powerful Ryzen processors. It supports PCIe 4.0, it’s made using the 7nm process, and its cache is sizable when compared to similar CPUs.

All in all, the 3800X is more than capable of handling the RTX 3080 and it does so without breaking the bank. However, a high-quality cooler is required when pushing this processor to its max frequency limit. Although the included Wraith Prism cooler is a good product, it’s not enough for the amount of heat generated at 4,5GHz.

6Intel Core I7-10700K

Architecture: Comet Lake | Socket: LGA 1200 | Cores/Threads: 8 / 16 | Base Frequency: 3.8 GHz | Top Boost Frequency: 5.10 GHz | TDP: 125W

Key Features:

  • Can be overclocked up to 5.1 GHz using Turbo Boost Max 3.0
  • Hyper-Threading technology
  • New overclocking controls for fine-tuning
  • Intel Optane Memory support

Next on our list we have the i7-10700K that makes a great alternative for the Ryzen 3800X. The base frequency is at 3,8 GHz, which is great for programs and games that take advantage of single-threaded performance. The processor also comes with the Turbo Boost technology that was previously used in the i9 line of CPUs. This allows us to boost the processor frequency up to a whopping 5.1 GHz. But as always, this means we need a strong cooling system to handle all the heat generated from so much power.

The i7-10700K can easily be paired with the RTX 3090, despite having only 8 cores and a smaller cache than the Ryzen alternatives. The high clock speeds manage to compensate. However, Intel hasn’t adapted this line of processors to the PCIe 4.0 interface, and therefore systems won’t be able to take advantage of the fast reading speeds provided by the next-gen tech.

7AMD Ryzen 7 3700X

Architecture: Zen 2 | Socket: AM4 | Cores/Threads: 8 / 16 | Base Frequency: 3.6 GHz | Top Boost Frequency: 4.40 GHz | TDP: 65W

Key Features:

  • PCIe 4.0 support
  • 7nm technology
  • 36MB GameCache memory for boosted performance
  • Wraith Prism Cooler included

The Ryzen 7 3700X is the budget alternative to the 3800X. The difference between the two isn’t enormous since it’s also an 8-core CPU and the max frequency is just 100 MHz lower. With a good cooler, we can obtain almost as much performance and it will be enough to unlock the RTX 3090’s potential. Therefore those who are restricted by their budget, especially after purchasing Nvidia’s top of the line GPU, still have a chance of building an excellent gaming system.

In addition, the 3700X requires less power than any other CPU on this list, with a requirement of only 65W. This is important because the RTX 3090 is a real power drainer, but if we use the 3700X processor we can get away with a smaller power supply.

Furthermore, PCIe 4.0 is standard with this CPU as well even though it falls into the budget category. This is good news because we can take advantage of faster than ever before SSDs that would run at slower rates on the PCIe 3.0 CPUs.

The Ryzen 7 3700X might not appear impressive at a first glance, but it comes with all the bells and whistles needed to properly enjoy the benefits provided by the RTX 3090.

Final Thoughts

Nvidia’s RTX 3090 is an impressive GPU that requires a good CPU for us to be able to enjoy all of its features and performance. But that doesn’t necessarily mean we need a Threadripper. All of the CPUs on this list will enable us to experience next-gen high-resolution gaming and some of them make the best workstations for dedicated visual artists and data scientists. Choose the one that suits your goals and your budget. Lastly, you can use this bottleneck calculator to better help you choose the right CPU for your RTX 3090 GPU.


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