A couple of months ago we ran a story about how gigabit broadband modems with the Intel Puma 6 chipset are suffering from massive latency spikes. At the time, Intel promised a firmware update would resolve this issue but today the Puma 6 latency spikes are back in the news as TechPowerUp reports that two firmware updates later, the situation is still a mess:
The modem I got was based on the Puma 6 chipset, which is an Atom based chipset from Intel. I immediately noticed a more sluggish web experience, despite the bandwidth nearly doubling (going from 8 downstream pipes to 24 will do that). I began to google this issue, and came up with a much-underreported issue from a thread on dslreports.com where the dedicated members there have extensively documented the issues with the Puma 6 chipset, and Intel's apparent inability to patch them.
The issue appears to be Intel's insistence on doing on the data processing of the mathematical channel separation (Full Spectrum Frequency Capture, which this modem utilizes, is a very mathematically intense operation) on a weak Atom CPU. The CPU bogs down under load, resulting in frequent latency spikes up to 250ms (that's like going around the globe twice, for reference). Intel for its part has put out firmware patches, but two fixes later and they are apparently unable to correct this issue beyond making ICMP work. TCP/UDP is still a mess, and guess what? That's what everyone uses.
This chipset is used by a lot of new cable modems so if you recently upgraded and suffer from sluggish web browsing or issues when playing games online the Puma 6 chipset may be the culprit.