SPEC’s CPU benchmark suite has been a long established industry standard, and is almost impossible to miss when reading through various publications. Intel used SPEC CPU2000 to showcase Pentium 4’s improvements over Pentium III. Samsung used SPEC CPU2000 and SPEC CPU2006 traces to tune their Mongoose cores. SPEC CPU2017 formed part of Intel’s performance projections for Lion Cove. Now, SPEC has updated their CPU benchmark suite with SPEC CPU2026. The new suite consists of 52 workloads, up from 43 in SPEC CPU2017. Individual workloads consist of more source code lines, measured in KLOC (thousands of lines of code). SPEC’s goal is to modernize their CPU benchmark suite, while retaining the portability goals that characterized SPEC.
Because of SPEC’s importance in the CPU performance world, I’ll be looking over the new suite’s workloads to examine the challenges that they serve up to CPUs. I’m interested in hardware rather than compiler comparisons, so I’ll be using GCC 14.2.0 with -O3 and native architecture/optimization targets. I did try GCC 15.2.0, but ran into various issues and decided to stick with GCC 14.2.0 to conserve time. I’m testing all of the systems below using Linux.
SPEC CPU scores represent speedup ratios relative to a reference system. Each SPEC CPU update tends to update the reference system, though not always to one that’s a relevant comparison for recent hardware.
An Ampere eMAG 8180 system provides the reference score of 1.0 for SPEC CPU2026. Ampere’s eMAG is faster than the Sun Fire V490 used for SPEC CPU2017, in much the same way that a Cessna 172 might be faster than a Sopwith Camel. Neither is a good comparison against modern airliners. Similarly, Ampere eMAG was not a widely deployed platform, and even systems that pre-date it by many years outperform it by a large margin. I’ve heard part of the motivation behind using a slower system was to let most systems achieve high scores, but that could have been accomplished by making the reference score a higher number, like 1000, instead of 1.0. Geekbench 6 takes a more reasonable approach, with a Core i7-12700 calibrated to a reference score of 2500. Unlike Ampere’s eMAG, Intel’s Core i7-12700 and similar CPUs were widely deployed across consumer systems, and Intel today uses a similar core architecture in Xeon 6.
Examples of Intel and AMD’s latest desktop CPUs show similar performance in SPEC CPU2026’s integer suite, while Zen 5 tends to pull ahead in floating point tests. I had to run SPEC CPU2026 on a Lion Cove core that only reached 5.5 GHz, because the two 5.7 GHz capable cores had trouble completing the test suite without crashes. There seems to be something wrong with my sample, but I suspect a Lion Cove core that does complete the tests at 5.7 GHz would narrow the gap.
Individual scores in the integer suite show Zen 5 and Lion Cove closely matched, as the aggregate scores would suggest. Absolute scores show just how far outmatched the Ampere eMAG system is. Current desktop cores obliterate ones in the Ampere eMAG, especially in 706.stockfish. Even the FX-8350, which is over a decade old, might be a better reference point. It also sails way past the eMAG system in nearly every test.