Investigating Cavium's ThunderX: The First ARM Server SoC With Ambition

ThunderX SKUs: What is Cavium Offering Today?

Cavium has been promising SKUs with 16 cores or 48 cores, with clockspeed ranges between 1.8 GHz and 2.5 GHz, with a TDP of up to 95W. While I am typing this article, Cavium has not published a full spec list of the different SKUs and the real silicon is different from the paper specs. So we will simply jot down what we do know.

The SKU we tested was the ThunderX-CP CN88xx 2 GHz. It is hard to identify the CPU as the usual Linux CPU identification tools do not tell us anything. Only the BIOS can gave some info:

The SKU we tested (CN8890), has 48 cores at 2 GHz, inside a TDP of 120W and costs around $800. This is the SKU that is being produced at mass scale.

What we know so far:

• SKUs available with Clockspeeds of 1.6 GHz and 1.8 GHz with lower TDPs than 120W (2 GHz)
• Highest clock is 2 GHz
• SKUs with 24, 32, and 48 cores
• Available in all families (Cloud, Storage, Security, Networking) and currently in productions

TDP ranges from 65W (low end, 24 cores at 1.8 GHz ?) to 135W (probably a 48-core SKU at 2 GHz with most features turned on).

But it is safe to say that Cavium missed the target of 48-cores at 2.5 GHz inside a 95W power envelope. That probably was too optimistic, given the fact that the chip is baked with a relatively old 28 nm high-k metal-gate process at GlobalFoundries.