In its 11th Measuring Broadband Australia report, the consumer watchdog said some monitored services were routinely attaining higher speeds than expected.
The report found that between 84.8% and 98.5% of maximum plan speeds were achieved by users with all RSPs during the hours of 7pm to 11pm, normally considered the busy period.
Additionally, the report said, more than half the services monitored achieved download speeds better than the plan specifications when averaged across the entire day.
The ACCC found that Telstra showed the biggest improvement in busy-hour download speeds, which were up by more than 11% since the last report.
For the first time, Superloop featured in the quarterly report, and achieved comparable results to other monitored RSPs with an average of 93.4% of maximum plan speed during busy hours.
“NBN Co’s decision to temporarily waive charges for up to 40% extra capacity for RSPs in the form of increased connectivity virtual circuit has played a key role in supporting broadband speeds during the pandemic,” Sims added.
But customers on fibre-to-the-node connections did not have things so good. The ACCC found that those on 50Mpbs and 100Mpbs connections experienced about 10% and 20% lower speeds respectively at any give time.
“Although most consumers have already benefitted from increased download speeds, those on FttN connections are continuing to experience lower than expected speeds," Sims said.
"We encourage NBN Co and RSPs to work to resolve this, especially given the additional investment in FttN services announced by NBN Co in September.
“Good progress has already been made on addressing this issue with the proportion of underperforming services in our sample falling from 13.9% in May 2018 to 8.1% in October 2020."
The report also found all major NBN plans could support at least one high-definition stream at a time. Plans on the 25Mbps tier were able to support at least one ultra-high-definition stream, and nearly all could support three simultaneous high-definition streams.
Reacting to the ACCC announcement, Optus vice-president for Regulatory and Public Affairs, Andrew Sheridan, commented: "We are very pleased with the independent speed test results released by the ACCC in their December Measuring Broadband Australia Report.
"Optus is number one for average download speeds during busy hours, for the fifth quarter in a row; all hours; and Netflix streaming during busy hours on the NBN 50 service.
"We know that our speed leadership makes a real difference to our customers’ experience, and will continue to strive to meet and exceed their expectations."