Ryzen 7800X3D preview - 7950X3D One CCD Disabled - Introduction

Ryzen 7800X3D preview - 7950X3D One CCD Disabled 

AMD has released its flagship desktop processor, the Ryzen 9 7950X3D, featuring the 3D Vertical Cache technology, which improves gaming performance. The processor holds two 8-core complexes/clusters, one has 64MB X3D cache, the other one has faster cores. We'll disable the core complexes and indicate what 7800X3D is going to offer in the near future.  The company has launched the 16-core 7950X3D and 12-core 7900X3D; the 8-core 7800X3D will join the lineup on April 8 and that part (to some degree) we can emulate. The 7950X3D and 7900X3D processors are designed to compete with Intel's "Raptor Lake" Core i9-13900K and Core i7-13700K processors, respectively, but they come with high price tags of $700 and $600, respectively. The Socket AM4 5800X3D is still popular among users, offering gaming performance equivalent to the 12th Gen "Alder Lake" processors. AMD's move indicates that gamers are content with buying an 8-core/16-thread processor, which is sufficient for gaming. These new processors come with a larger L3 cache size of (+64MB) and feature the manufacturer's own 3D V-Cache stacked atop a CPU chiplet and the cache found in the Ryzen 7000 CPUs. The new Ryzen 7000 X3D models will feature 8, 12, and 16 cores. While the current Ryzen 7 5800X3D is still a top-tier option for gamers, the Ryzen 7000 X3D components benefit even more from 3D V-Cache due to the increased bandwidth, which will enhance performance in games and specific creation workloads and applications. The suggested pricing of these processors is as follows:

• Ryzen 9 7950X3D for $699
• Ryzen 9 7900X3D for $599
• Ryzen 7 7800X3D for $449

Best of all, these parts will be available in the market very soon. The Ryzen 9 7950X3D and Ryzen 9 7900X3D processors will be on sale beginning today, February 28th, the Ryzen 7 7800X3D will be available on April 6th.

Emulating the 7800X / 7800 X3D

AMD has decided to delay the launch of their 8-core 7800X3D processor in favour of promoting their 12-core and 16-core 7000X3D processors. The 7950X3D and 7900X3D utilize two 8-core CPU core complex dies (CCD), with one die having a 3D Vertical Cache and the other without one (a regular 8-core die). This allows gaming workloads to use the 3D V-cache CCD while the other CCD steps in only as needed, or of preferred can be utilized for applications that require higher clock frequencies. For non-gaming workloads, both CCDs can be used for parallelism. To emulate the performance of a 7800X3D, we'll disable each CCD of the Ryzen 9 7950X3D processor was disabled, leaving it with just the 96 MB L3 cache while the other has that extra +64MB L3. The resulting numbers indicate what to expect from the 7800X3D, despite differences in clock speeds and boosting behaviour.

To accomplish this, we went deeper into the motherboard UEFI BIOS; our ASUS Hero board allows disabling each of the CPU cores per CCD ) as shown above). In turn, we disabled each CCD, so we can test and emulate an 8-core 'regular' as in 7800X processor, and then switch towards the other CCD (00), which is the one with the extra 64Mb L3 cache (X3D).

All of this is, of course, a bit in its base emulation as clock frequencies per core differ somewhat and are not 100% in line with the pending 7800X3D. This experiment brings performance numbers that can give potential buyers a good idea of what to expect from the up-and-coming 7800X3D and whether it is worth the wait and cost savings. Again, it should be noted that this trick is not a perfect simulation of a 7800X3D, as the clock speeds and boosting behaviour may differ slightly from the actual processor. However, as you will notice, for gaming, the 7800X3D might be the best deal to get.

Our test reveals that CCD00 (the one highlighted in red) holds the X3D core, and the right CCD001 is the regular one (higher clocks). In this article, we'll try out each core complex isolated to examine what effect that extra L3 cache brings.