A close-up image of AMD's RX 7900 XT (opens in new tab) reveals what appears to be a connection point used in 3D chip stacking technology. Engineer Tom Wassick zoomed in on a memory chiplet within the Navi 31 GPU, known as the MCD, and found a small "spot" that appears to be similar to AMD's V-Cache CPU.

According to Wassick, who observed AMD's latest GPU with an infrared camera (via Tom's Hardware (opens in new tab)), these spots may indicate the potential ability of the RDNA 3 GPU to allow AMD to stack another chip on top of the MCD They say that it is possible.

It had been rumored that AMD would implement a stacked MCD in the Navi 31 GPU development process, but they have reportedly decided against it, at least for the first chip. There are also contrasting rumors of a Navi 31 refresh later this year, but such a refresh has been dropped (open in new tab).The potential to dramatically increase the cache available on the RX 7900 series cards would be a powerful weapon for AMD, as a later update to the potential would have been a powerful weapon.

These connection points could either be legacy connections from older plans for GPU memory dies or pave the way for future upgrades. In theory, however, GPUs could benefit from having more memory on hand, just as CPUs do.

AMD has found that both the latest GPUs and CPUs benefit from performance gains by increasing cache capacity; the Infinity Cache introduced in the Ryzen 6000 series graphics cards helps increase the available memory bandwidth and is the first processor with 3D V- Cache technology, the Ryzen 7 5800X3D (open in new tab), the first processor with the technology, runs significantly faster than the Ryzen 7 5800X on cache-intensive workloads (such as gaming). A similar performance boost is expected for the V-Cache (open in new tab) chip in the upcoming Ryzen 7000 series, which is set to battle Intel's Raptor Lake processors in February. The current Ryzen 7000 series tends to lose this battle, but the 3D V-Cache chip is expected to be more competitive and possibly top the performance charts.

Nvidia has also followed AMD's lead by significantly increasing the L2 cache on its RTX 40 series Ada Lovelace-based graphics cards, and AMD will no doubt look to other implementations of this technology to again maximize performance.

Both the RX 7900 XT and RX 7900 XTX (open in new tab) have chiplet-based GPUs, which will play an important role if AMD seeks to enhance the amount of cache in the GPU with chip stacking technology.

The Navi 31 GPU is divided into two parts, the GCD and the MCD; the XTX has six MCDs and the XT has five MCDs, but instead of a sixth MCD, there is a dummy silicon block, making it look like the XTX. In theory, AMD could expand the number of memory chiplets with 3D V-Cache without expanding the overall GPU footprint.

Unfortunately, this is only a pipe dream, but signs of chip stacking capabilities may hint at what is to come from the Red Team. At this point, we expect inexpensive graphics cards from the RDNA 3 architecture to be released quickly, but we will keep an eye on the development of chiplet-based 3D stacked behemoths to see if they emerge. However, as for chiplet-based 3D-stack behemoths, stay tuned for future developments.