Building large monolithic many-core CPUs is extremely hard even for renowned chip designers. For Chinese CPU developers, many of whom do not have access to leading-edge production nodes, the only way to build a processor with high core count is to adopt a chiplet design. As it turns out, this is exactly what Chinese CPU maker Loongson does with its 32-core 3D5000 processor, Sina reports.
Earlier this year Loongson began to ship its 3C5000 processor that relies on 16 LA464 cores featuring the company’s LoongArch microarchitecture, up to 64MB of cache, and four 64-bit DDR4-3200 memory interfaces with ECC support. The Loongson 3D5000 takes two 3C5000 CPUs and places it on a single piece of substrate to build a 32-core processor with eight memory channels. The 32-core processor supports up to 4-way simultaneous multiprocessor configurations and therefore it is possible to build a server with up to 128 cores.
Loongson recently completed verification of its 3D5000 processor, the report says. The CPU reportedly consumes 130W at 2.0 GHz as well as 170W at 2.20 GHz. Loongson’s 3D5000 CPU comes in an LGA-4129 packaging.
While building a 32-core CPU based on a proprietary microarchitecture is an achievement, it should be noted that product is a way to test ability to build a chiplet-based design. While China-based SMIC — which produces processors for Loongson — slowly adopts more advanced nodes, it is significantly behind market leader TSMC. Therefore, companies like Loongson cannot offer products that are comparable to those from AMD and Intel.
Chiplets represent a real opportunity for Loongson to build rather serious processors and servers platforms with significant number of cores and proprietary microarchitecture enhanced for servers and supercomputers. Meanwhile, we have no idea whether other CPU developers from China will follow the suit.
When it comes to performance, Loongson says that its 32-core 3D5000 CPU scores 400 points in the SPEC CPU2006 base test, whereas the result of a 2-way 32-core 3D5000-based machine exceeded 800 points in the SPEC CPU2006 base benchmark. The CPU designer believes that a 4-way machine will hit 1600 points.
Loongson is gearing up to ship samples of its 32-core processors in the first half of 2023, whereas commercial versions will be shipped later.