What is “Cascade Lake (CSL-X)”?
It is one of the 10th generation Core X-Series arch (CSL-X) from Intel – the latest revision of the “Skylake-X” (SKL-X) arch; it succeeds the older 9900 and 7900 X-Series for HEDT platform. Again, as on the desktop/mobile – it is not the “real” 10th generation Core-X arch – but unlike those platforms – it does actually bring a few more features thus it may be thought as “gen 9.5”:
- Up to 18C/36T (matching older 7/9-X series)
- Increased Turbo ratios (e.g. 3.0/4.6GHz for 10980X vs. 2.6/4.2 for 7980X)
- 4-channel DDR4-2933 (up from 2667) and 256GB (up from 128)
- AVX512-VNNI, aka “Deep Learning Boost” (DLB) for AI/ML neural networks
- Hardware fixes/mitigations for vulnerabilities (“Meltdown”, “MDS”, various “Spectre” types)
- Reduced cost – by 50% ($999 for 10980X vs. $1999 for 7980X)
Unfortunately there are no core-count increases here as the CPUs are still power limited especially with AVX512 loads, but we do have some base and turbo ratio increases that should come in useful. We also get a good increase in (official) memory data-speed support and double memory size support (256GB!) for those big servers.
New instruction sets are always appreciated, though “VNNI” is just an acceleration for twin 8/16-bit integer multiply/accumulate for faster sumation for low-precision quantised (thus integer not floating-point) neural networks. Thus it is not something most algorithms can benefit from: if all you’re going to be using your CPU is AI/ML then great – otherwise it may not be much use.
Dropping the price by a *huge* 50% instantly doubles performance/cost ratio making the CSL-X far more competitive against the new Ryzen 3 / ThreadRipper 3 that have brought big performance gains. Alternatively, it also allows almost doubling the no. of cores/cost – which is a nice upgrade for lower-end users but will not help top-end (12C+) users.
Why review it now?
Until “IceLake” (ICL-X) makes its public debut, “Cascade Lake” is the latest X-Series CPU from Intel you can buy today; despite being just a revision of “Skylake-X” due to its reduced price they may still prove worthy competitors not just in cost but also performance.
As they contain hardware fixes/mitigations for vulnerabilities discovered since original “Skylake-X” has launched (especially “Meltdown” but also various “Spectre” variants), the operating system & applications do not need to deploy slower mitigations that can affect performance (especially I/O, virtualisation) on the older designs. For some algorithms, this may be enough to warrant an upgrade alone!
In this article we test CPU core performance; please see our other articles on:
- Intel Core i9 10980X (Cascade Lake) Review & Benchmarks – 4-channel @ 3200Mt/s Cache & Memory Performance
We are comparing the top-of-the-range Intel ULV with competing architectures (gen 8, 7, 6) as well as competiors (AMD) with a view to upgrading to a mid-range but high performance design.
|CPU Specifications||Intel Core i9-10980X (CSL-X)
||Intel Core i9-9900K (CFL-R)
||Intel Core i9-7900X (SKL-X)
||AMD Ryzen 9 3950X (R3)
|Cores (CU) / Threads (SP)||18C / 36T||8C / 16T||10C / 20T||16C / 32T||CSL-X has the most cores thus a big advantage.|
|Speed (Min / Max / Turbo)||3.0 – 4.6GHz||3.6 – 5.0GHz||3.3-4.3GHz||3.8-4.6GHz||CSL-X improves Turbo clock over SKL-X|
|Power (TDP)||165 – 250W||95 – 135W||140 – 250W||105 – 135W||TDP has increased over SKL-X|
|L1D / L1I Caches||18x 32kB / 18x 32kB||8x 32kB / 8x 32kB||10x 32kB / 10x 32kB||16x 32kB / 16x 32kB||No L1 change|
|L2 Caches||18x 1MB (18MB)||8x 256kB (2MB)||10x 1MB (10MB)||16x 512kB (8MB)||No L2 change and good size vs. Ryzen3|
|L3 Caches||24.75MB||16MB||13.75MB||4x 16MB (64MB)||L3/Core stays the same – too little vs. Ryzen3|
|Microcode (Firmware)||MU065507-29||MU069E0C-9E||MU065504-49||MU8F7100-11||Just a stepping change of the same core|
We are testing native arithmetic, SIMD and cryptography performance using the highest performing instruction sets (AVX2, AVX, etc.). “CometLake” (CML) supports all modern instruction sets including AVX2, FMA3 but not AVX512 (like “IceLake”) or SHA HWA (like Atom, Ryzen).
Results Interpretation: Higher values (GOPS, MB/s, etc.) mean better performance.
Environment: Windows 10 x64, latest AMD and Intel drivers. 2MB “large pages” were enabled and in use. Turbo / Boost was enabled on all configurations.
Thanks to AVX512 CSL-X manages to easily beat Ryzen3 in heavily vectorised algorithms (up to 50% faster) and also in memory-bandwidth heavy algorithms (due to its 4-channels memory sub-system). But, despite having 2 extra cores, on older AVX2/FMA we pretty much have a tie – not something we are used to see from Intel.
Also, the improvement over older SKL-X is exactly in-line with the increase in cores (18 vs. 10 here) – thus there are no appreciable core improvements to boost performance. Without specific VNNI-accelerated algorithms, there is no point for SKL-X users to upgrade: you do get more cores for a lot less money but your hardware is also worth a lot less.
It shows how much Ryzen3 has improved (especially due to 256-bit width AVX2/FMA units) and ThreadRipper with 4-channels and even more cores (up to 32!) and threads (up to 64!) should nullify Intel’s AVX512 benefit.
SiSoftware Official Ranker Scores
Final Thoughts / Conclusions
For many, it may be disappointing that we do not have the brand-new “IceLake-X” (ICL-X) now rather than a 3-rd revision “Skylake-X” – and indeed “Cascade Lake-X” (CSL-X) does struggle against newer (and older) competition to make its mark. Without core-count increases and with minor clock increases while still very limited by power at the high end it just does not bring enough improvement. The only exception are workloads (low-precision quantised neural networks) that can use AVX512-VNNI.
Indeed, its “ace card” is the 1/2 price reduction vs. old 7/9-X series and that just about makes it competitive; thankfully existing X299 mainboards can use it through a BIOS/ME update – although boards are still expensive.
But the competition (AMD Ryzen 3, ThreadRipper 3) has much higher performance these days while older CPUs (Ryzen 2 / ThreadRipper 2) have also been greatly reduced in price. They also can use older boards, although to use new features (PCIe 4.0, better power management) new boards are required.
All in all, Intel has done all it can – fix vulnerabilities, greatly reduce the price – to keep the X-Series competitive with current designs – and that it has pretty much achieved. The next X-Series arch better deliver otherwise it will be dead and buried.
In a word: Recommended due to 1/2 price drop
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