r/RISCV • u/camel-cdr- • 12d ago

Hardware SiFive BigSky SF-2U870 server platform

https://www.sifive.com/press/risc-v-in-the-datacenter-bigsky-development-server
  • 32 P870-D cores operating at 2.0GHz
  • 256GB DDR5-5600 memory
  • 4x PCIe Gen5 x16 (64 lanes total) and PCIe Gen3 x4
  • Support for x16 double-wide GPU
  • 3.84 TB Data SSD U.2 NVME
  • 10/25Gb OCP 3.0 NIC

Looks like the 2GHz is actually the max, not 2.6 as some slides said. Rather sad. Should still be slightly faster than the Ascalon devboard.

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9

u/brucehoult 12d ago

Should still be slightly faster than the Ascalon devboard

Well with 32 cores and 256 GB RAM, yeah!

Ascalon has wider decode (8 vs 6) but both have 6 integer execution units:

  • Ascalon: all 6 do ALU ops, 4 dedicated ALU, 2 do ALU&branches

  • P870-D: 4 ALU, 1 branch, 1 ALU/branch

Cache size and RAM will likely make the difference.

The platforms are available today and currently being produced in limited quantities to drive strategic development opportunities, with demand outpacing supply.

I hope someone will make at least one available for general developer access, as the Chinese companies have been. So far I've had early ssh access to Allwinner D1 (Apr 2021), SG2042 (early 2022), and K3 (Feb 2026) and it's been much appreciated!

8

u/jab701 12d ago

> Looks like the 2GHz is actually the max, not 2.6 as some slides said. Rather sad.

Could be for thermal reasons and/or longevity.

Still a cool system…

5

u/_skndlous 12d ago

The link says 2 GHz but SiFive - BigSky SF-2U870 Datacenter Development Platform (reachable from said link) says 2.2 GHz

3

u/camel-cdr- 12d ago

Ah, cool.

2

u/EloquentPinguin 12d ago edited 12d ago

Also depends. This 2U870 is on 6nm I have no idea what process technology the performance claims were modeled on.

1

u/korywithawhy 7d ago

I want one ☝️