AMD Ryzen third-generation and the latest PCIe4.0, what practical improvements you can get

Sajjad Hussain
Oct 21 · 8 min read
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Since AMD released the third-generation Ryzen desktop processor, PCIe4.0 has often appeared in the eyes of players. So what is the role of PCIe4.0 and what practical improvements can it give us?

What is PCIe4.0?

The PCIe specification is the PCI-Express specification, which can generally be translated into a high-speed connection standard for peripheral devices. It is formulated by the PCI-SIG organization. Currently, there are many top companies in the IT industry among its members. The PCIe specification is a PC connection standard proposed in 2003. The PCIe channel contains two data channels to better ensure the efficiency of data reception and transmission. Each device has an independently allocated bandwidth and does not occupy the total bandwidth. The PCIe specification has always been the mainstream transmission connection standard on the PC.

We currently use the most widely used PCIe3.0 standard that was actually formulated 10 years ago (2010), and the PCIe2.0 standard, which is still used by some devices, was formulated in 2006. PCIe 2.0 adopts 8b/10b encoding method and has a signal rate of 2.5GT/s. PCIe3.0 encoding method is modified to 128b/130b, and the signal rate increases to 8GT/s, while PCIe4.0 doubles again to achieve 16GT/s. Therefore, in terms of bandwidth, PCIe3.0 is 32GB/s at ×16 bandwidth, while PCIe4.0 is doubled to 64GB/s.

The greater the bandwidth, the greater the throughput, which means that the amount of data passing at the same time is greater. It is like the wider the road, the more vehicles can pass at the same time. Reflected in the PCIe bandwidth, that is, PCIe4.0 can reach the bandwidth of PCIe3.0 at ×16 at a bandwidth of ×8. The high bandwidth provides greater help for transmission and communication between devices.

Platform comparison highlights PCIe4.0 high bandwidth advantage

We all know that the direct PCIe channels for consumer desktop processors are very limited. In terms of current mainstream processors, Intel’s tenth-generation Core flagship i9 10900K currently only has 16 direct-out PCIe channels. AMD’s third-generation Ryzen flagship For example, Ryzen 9 3900X has 20 direct PCIe channels. The number of straight-out channels determines the number of devices connected to the processor at a high speed.

On the Intel platform, when only one graphics card is inserted into the PCIe×16 slot of the direct-connected processor, PCIe3.0×16 full speed can be achieved, but if dual graphics cards SLI or CFX are used, only 8+8 channels can be used. When three PCIe devices are connected, they can only be allocated as 8+4+4. With a limited number of PCIe channels, the connection speed of multiple devices will be reduced. When multiple high-performance PCIe devices are connected, full performance cannot be achieved.

On Intel’s current consumer-level platforms (such as Z390, Z490), in most cases, the first PCIe3.0×16 slot on the motherboard is directly connected to the processor, while storage devices such as NVMe are used. It is the PCIe channel provided by the motherboard chipset, not the PCIe channel directly connected to the processor. In the Intel platform, the motherboard chipset and the CPU use the DMI bus (based on PCIe bus), and the bandwidth is the same as PCIe3.0×4 8GB/s. That is to say, although the motherboard can provide up to 24 PCIe channels, because the communication bandwidth with the processor is only PCIe3.0×4, when various high-speed transmission devices are running at the same time, the full speed cannot be achieved due to bandwidth limitations.

AMD’s third-generation Ryzen platform not only provides PCIe4.0, but also provides 4 more channels for NVMe

In AMD’s third-generation Ryzen platform, first the processor provides 20 PCIe4.0 channels. Corresponding to the B550 and X570 motherboards, it can be directly divided into PCIe4.0×16 direct connection for graphics cards and NVMe PCIe4.0×4 is directly connected. In the case of a single NVMe, the storage does not have to preempt the graphics card channel in order to run at full speed. At the same time, the communication bandwidth of AMD’s third-generation Ryzen processor and motherboard (B550/X570) chipset has also been upgraded to PCIe4.0×4, which can provide 16GB/s bandwidth, which can better meet the needs of multiple high-speed devices at the same time. Bandwidth requirements at work.

Measured and analyzed the specific performance of PCIe4.0 high bandwidth

When AMD’s third-generation Ryzen processor was launched last year, after announcing support for PCIe 4.0, AMD’s own RX 5700/5700XT first implemented graphics card support for PCIe 4.0 on consumer platforms. With the introduction of NVIDIA RTX 30 series graphics cards Launched, the mainstream graphics cards currently on the market have all realized support for PCIe4.0. At present, the application of PCIe4.0 is mainly concentrated on graphics cards and NVMe SSDs.

We used NVIDIA RTX 3080 to test PCIe 4.0, and used the third-generation Ryzen processor + X570 motherboard and tenth-generation Core + Z490 motherboard for comparative testing. From the PCIe bandwidth test of 3DMark, the bandwidth test of the RTX 3080 on the third-generation Ryzen processor + X570 motherboard supporting PCIe 4.0 reached 26.17GB/s, while on the tenth-generation Core + Z490 motherboard that only supports PCIe 3.0 The above is only 12.93GB/s bandwidth, it can be clearly seen that PCIe 4.0 is twice the bandwidth of PCIe 3.0.

In this generation of flagship graphics cards, although the high bandwidth of PCIe4.0 is obvious in the test, in daily applications, due to various reasons, it is still unable to fully consume the full bandwidth performance of PCIe4.0, so for now, Its impact on the performance of the graphics card is still very small, but this does not mean that the high bandwidth of PCIe4.0 is useless, because the performance and bandwidth requirements of the future graphics cards will definitely be higher and higher, and the impact of bandwidth on the performance of flagship graphics cards will gradually appear. come out.

The biggest impact on players, and the most intuitive feeling at present, is the direct improvement in performance brought by storage. So we also conducted PCIe4.0 tests on storage.

Testing platform:

Processor: AMD Ryzen 7 3700X

Memory: Gigabyte AORUS DDR4 3200 8GB×2

Motherboard: Gigabyte B550 AORUS MASTER

Hard Disk: Gigabyte PCIe Gen4 1TB NVMe SSD

In this test, we chose the PCIe4.0 test combination of Gigabyte B550 AORUS MASTER and Gigabyte PCIe Gen4 1TB NVMe SSD.

GIGABYTE B550 AORUS MASTER is built in accordance with the flagship X570 motherboard specifications. It is equipped with 16-phase direct-out digital power supply. Each phase power supply current is up to 70A. This specification has exceeded most X570 motherboards on the market, even with AMD Ryzen It is easy to use a flagship processor with 105W TDP like 9 3950X, and there is no pressure to upgrade Zen3 in the future. The design of the storage part is a big selling point of Gigabyte B550 AORUS MASTER. According to the official specifications, the B550 could originally provide a PCIe 4.0 × 4 M.2 slot directly from the third-generation Ryzen, while the Gigabyte B550 AORUS MASTER provides three PCIe 4.0 × 4 M.2 slots. From the third-generation Ryzen processors, two of which are PCIe 4.0 x 16 channels from the graphics card. In this way, Gigabyte B550 AORUS MASTER can support 3 PCIe 4.0 solid state drives to form a RAID0 system, providing a read and write speed of more than 12000MB/s (about 4 times the speed of a single high-end PCIe 3.0×4 solid state drive). Professional design applications with extremely high material import speed are very valuable in terms of practicality. In addition, Gigabyte B550 AORUS MASTER is also equipped with a 6-layer PCIe 4.0 dedicated 2-oz copper PCB, which can fully ensure the stability of signal transmission.

From the test point of view, the continuous read speed of a single PCIe 4.0 SSD on the Gigabyte B550 AORUS MASTER has reached about 5GB/s, and the continuous write speed has also exceeded 4GB/s, which has far exceeded the PCIe 3.0 top-level solid state drive. There are so many hard drives.

Since this motherboard can divide the PCIe4.0 channel of the processor into NVMe, so as to implement three PCIe4.0 M.2 interfaces on the B550 motherboard, we also used this feature to conduct a PCIe4.0 RAID0 test. From the test results, 3 PCIe 4.0 × 4 M.2 slots on the motherboard to form a RAID0 system, continuous reading and writing can exceed 12000MB/s, this performance can be said to be very scary.

So in what aspects can such performance bring us intuitive feelings? The third-generation Ryzen processor has a very strong performance in terms of multi-threading performance, and has become the preferred platform for professional creative workers. The high-performance processor combined with the faster read and write PCIe4.0 NVMe SSD can greatly accelerate The copying and loading time of engineering materials significantly improves the use experience and work efficiency.

Why do you say that? Take video shooting and editing as an example. With the release of Canon EOS R5, 8K RAW format video has officially announced its entry into the consumer market. In 8K RAW format, a few seconds of video material has reached the capacity calculated in GB. Both the copying and loading of the file impose greater requirements. Although 8K video is not the current mainstream, the demand for 6K and 4K video projects taken by video machines represented by Panasonic S1H and Sony A7S3 has become more and more prominent. In large-scale projects, such materials are still copied and edited. Loading puts forward higher requirements. At this time, using PCIe4.0 NVMe can greatly reduce the mutual copying and loading time of materials, which is more convenient and better to complete. Previously, multiple mechanical hard disk arrays could be used to complete It greatly simplifies the work process and improves work efficiency.

So in terms of graphics cards, in addition to the higher bandwidth requirements of future flagship graphics cards just mentioned, is there any more practical significance? This is a combination of many aspects. We have just mentioned that there is a relatively large limit on the number of PCIe channels in consumer processors. Therefore, with a limited number of channels, a higher bandwidth of a single channel can better save the number of channels. As the current mainstream graphics cards have been fully switched to PCIe4.0, this is more practical.

We all know that PCIe4.0 only needs half the number of lanes of PCIe3.0 to achieve the same bandwidth, so in the future, after mainstream devices are switched to PCIe4.0, channel allocation will be more convenient, such as entry and mid-end graphics cards. There is no need to use ×16 channels because they have relatively low bandwidth requirements. Using ×8 channels can achieve the previous PCIe3.0×16 bandwidth without affecting performance, so that More channels are used by other devices. For storage systems, PCIe 4.0×2 can achieve the bandwidth of previous PCIe 3.0×4. For entry-level NVMe that does not pursue performance, it only needs fewer channels to meet product positioning needs. So as to realize the equipment of larger capacity, it is also a flexible solution.

High bandwidth is more flexible, AMD Ryzen platform is more efficient with PCIe4.0.AMD’s third-generation Ryzen processors have brought PCIe 4.0 into the consumer market. With the development of the market for one year, PCIe 4.0 NVMe SSDs have gone from a state of high performance/high price when they first went on the market. It has reached a level close to the flagship PCIe3.0 NVMe SSD, and many storage brands have also released more PCIe4.0 NVMe SSD products. With the high bandwidth of PCIe4.0, the SSD using PCIe4.0 has also achieved a further breakthrough in speed. Samsung’s just released flagship NVMe SSD 980Pro can even reach 7000MB/s, which is very scary, and it also allows us to see more high-speed storage. Application environment. With the launch of NVIDIA RTX 30 series graphics cards, all mainstream graphics cards currently on the market have all realized support for PCIe 4.0, which will further promote the development of PCIe 4.0 and better utilize its high bandwidth advantages. It can be said that supporting PCIe4.0 is the current mainstream trend. In this case, AMD B550/570 platform that can support PCIe4.0 has become a more future-proof and reasonable choice.

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