Running SwOs Lite 2.14 on CSS610-8G-2S+IN switch. When Intel vPro AMT PC is in S3, it connects at 100Mbps (preferring 10Mbps if available). When PC is fully powered (S0), AMT connects at 1Gbps.

Unlike another switch, unable to set auto-negotiation link speeds for AMT on CSS610. Hoping for future SwOs Lite update to gain this feature. Presently, it's a choice between forcing 100Mbps (losing 1Gbps in S0) or accepting sluggish 10Mbps in S3.

When does your device enter S3 state? According to certain intel doc:

S3 Sleeping State: The S3 sleeping state is a low wake latency sleeping state where all system context is lost except system memory. CPU, cache, and chip set context are lost in this state. Hardware maintains memory context and restores some CPU and L2 configuration context. Control starts from the processor’s reset vector after the wake event.

IMO 10Mbps vs. 100Mbps doesn't matter much in this state. It'll take ages (compared to latency difference between 10Mbps and 100Mbps) for device to react ... my (a bit aged) HP laptop needs a second or three to wake up from sleep mode (yes, that's sleep, not hybernate) and a few miliseconds doesn't make any difference. And AFAIK in S3 sleep state only WoL packets matter, so not a big data volume either.