AMD Ryzen 9 5900X Review

AMD Ryzen 9 5900X Review

The AMD Ryzen 9 5900X has 12 cores and is the fastest mainstream gaming CPU we’ve seen so far. AMD’s Zen 3 architecture demonstrates how a little process and design modification can make a big difference in desktop processors. There’s no reason to acquire an Intel processor for that gaming PC you’re putting together with it. This CPU might be the best option available.

Features and Chipset:

The AMD Ryzen 9 5900X processor has 12 cores and 24 threads, with a boost clock of 4.8GHz. It has the same 105W TDP as the AMD Ryzen 9 3900X, but only reaches 142.27W in our testing, compared to 145.3W for the 7900X. The most significant architectural difference between Zen 2 and Zen 3 is that each CCX now has access to a full 32MB of L3 cache, rather than the 16MB available on Zen 2.

It’s likely that if you buy a motherboard that supports the new AMD Zen 3 processors, it will work with them. The new processors will be supported by some X470 and B450 motherboards, but not all. The AMD Ryzen 9 5900X attained a maximum temperature of 86°C during our testing, and that was with a 360mm AIO cooler mounted. The Intel Core i9-10900K reached a maximum temperature of only 73°C.


With a base frequency of 3.7GHz and a possible boost rate of 4.8GHz, it contains 12 cores and 24 threads. This is intended for more serious work, but it may also be used for gaming. It does not come with a cooler, although it does have the same 105W TDP as its predecessor. For threaded workloads, Zen 2 chips are expected to reach 4.2GHz, and for single-threaded applications, up to 4.95GHz. In addition, AMD’s Precision Boost 2 technology allows the CPUs to boost frequencies on the fly. The fact that the 5900X has beaten the maximum boost clock on multiple occasions indicates that AMD isn’t overhyping these new CPUs.


The Zen 3 microarchitecture from AMD isn’t all that different from the Zen 2 microarchitecture, although it does promise considerable performance gains. AMD claims a 19% increase in IPC over Zen 2 and access to 32MB of L3 cache for eight cores instead of four. 

Zen 3 does not employ TSMC’s upgraded 7nm+ manufacturing process but instead uses the same 7nm manufacturing process as Zen 2. Due to changes in the layout of AMD’s Zen 3 processors, each core now has access to a larger block of L3 cache. This implies AMD can make CPUs with up to eight cores utilizing just a single CCX and the I/O die that goes with it.

The upgrade from two four-core CCXs to eight-core chiplets may not appear to be significant on its own, but it has a significant impact on gaming performance. AMD is sticking to the AM4 platform’s 142W power envelope, which allows it to drop the base frequency by 100MHz across its new CPUs. The new AMD Infinity Fabric chips are backward compatible with motherboards from the 400 and 500 series. 

Although we had no issues operating the new processors with older RAM, the official memory support standard remains DDR4-3200. Those with older B450s and X470s will have to wait until January to acquire the necessary BIOS updates. Focus on a motherboard that uses the A520, B550, or X570 if you’re wanting to create a new system around these new processors.


The AMD Ryzen 9 5900X is the fastest mainstream processor we’ve ever tested, and it isn’t even close to Intel’s Core i9-10900K. Only the Time Spy physics test, which isolates the CPU score rather than reporting the entire score, gives Intel the upper hand. In Geekbench 5 multi-core testing, the AMD Ryzen 9 5900X is now 24 percent faster than the Intel Core i9-10900K, up from 11 percent gen-on-gen.

The advantage grows to 31% in Cinebench R20, which simulates rendering for creative applications. The AMD has the smallest advantage in pure CPU performance in the SISoft Sandra CPU Arithmetic test, where it is only 18% ahead. However, that is still a big advantage. This is one of the most significant processor generational advances we’ve seen.

A Brief Look at Overclocking and Thermals:

The AMD Ryzen 9 3900X and Ryzen 9 3950X, both Zen 2 mega-core monsters, have very little overclocking headroom out of the box. While I was able to accomplish stable overclocking of the CPU ranging from 1% to 14% depending on the number of cores I was clocking, the real-world yields of those systems did not reflect a performance improvement in the same way. Overclocking was the issue that the top of AMD’s Zen 2 stack grappled with the most.

In the case of the AMD Ryzen 9 5900X, the story was similar. Despite overclocking the chip in every combination I could think of, I couldn’t get a result that was better than what I got with the non-overclocked default clocks.

This indicates that Zen 3 has been meticulously designed, with AMD leaving very little to chance. Most purchasers should be able to unlock nearly all of this chip’s potential right out of the box, without the need for any special changes.


Overclocking AMD’s processors have felt like a futile activity for a few generations, and Zen 3 doesn’t change that. You can overclock it and get a boost in multi-core speed, but single-core performance will suffer as a result. Even if a few games improve slightly when overclocked, several will run poorly.


  • Gaming performance is now on par with, if not better than, the Intel Core i9. It also produces record-breaking content creation outcomes for its price range. 
  • Compatible with the AM4 socket 
  • TDP is low in comparison to Intel’s offerings.


  • There is no cooler included in the package. 
  • If you’re simply buying it for gaming, it’s a bit pricey. There’s not a lot of area for overclocking.


Looking for the peak of speed and value desktop CPU market? The new pacesetter is AMD’s Zen 3-based Ryzen 9 5900X, which outperforms Intel’s Core i9-10900K on all fronts.

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