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> Why are these only 1.4ghz frequency, when raspberry pi gets to 2.4ghz? Milk-V Megrez is shipping the same SoC running at 1.8 GHz. Intel's Horse Creek chip w
by brucehoult 2y ago
> Why are these only 1.4ghz frequency, when raspberry pi gets to 2.4ghz?
Milk-V Megrez is shipping the same SoC running at 1.8 GHz.
Intel's Horse Creek chip with the same cores ran at 2.4 GHz, but Intel is in trouble and cancelled non-core activities. A working board was shown at Hot Chips 23.
Clock speed depends on the SoC integrator at least as much as the core designer, and the process node it is made on. And the packaging thermal envelope.
> Or does the architecture not really support faster chips?
Of course not. From as technical point of view it's essentially identical to Arm64, and with the same financial investment and comparable engineers will run at the same speed.
The P550 is a very early RISC-V design, announced in June 2021, just a few months after the RVA22 spec it implements was published. Three to four years to go from core to SBC is normal in the industry, including for Arm's A53, A72, A76.
SiFive has designed and shipped two or three major generations of more advanced cores since then, in the P670, P870, and P870-D.
- drmpeg 2y agoIs the P550 RVA22? Here's the ISA string in Linux. Seems like a lot is missing. rv64imafdch_zicsr_zifencei_zba_zbb_sscofpmf
- brucehoult 2y agoOops! You're right. They only claim RV64GBC https://www.sifive.com/document-file/p550-core-data-sheet https://www.sifive.com/document-file/p550-core-data-sheet Although that was at announcement in June 2022. SiFive have continuous improvement and quarterly updates, which is how the U74 in the JH7110 ended up with Zba and Zba that the FU740 (and I thin JH7100) doesn't have, but missed out on the L2 prefetcher that the next quarterly updata got. We do know that the Eswin chip has H, right?
- brucehoult 2y agoActually Eswin doesn't seem to claim B extension: https://www.eswincomputing.com/en/bocupload/2024/06/19/17187920991529ene8q.pdf https://www.eswincomputing.com/en/bocupload/2024/06/19/17187... But Intel Horse Creek did (and also was higher MHz, they said 2+ GH, but I think they demoed it at 2.2 at Hot Chips and were shooting for 2.4 in production): https://community.intel.com/t5/Blogs/Tech-Innovation/open-intel/What-s-in-store-for-the-latest-RISC-V-development-board/post/1448348 https://community.intel.com/t5/Blogs/Tech-Innovation/open-in... All will be revealed in 10 days or so.
- camel-cdr 2y agoIt should support rv64imafdch_zicsr_zifencei_zba_zbb_sscofpmf with version 0.6 of the H extension. The the confusion reguarding B probably comes from claimes of B support before ratification, where it wasn't clear that Zbs needs to be supported. See the discussion here: https://github.com/llvm/llvm-project/pull/122164#issuecomment-2580676443 https://github.com/llvm/llvm-project/pull/122164#issuecommen...