The highest capacity undersea cable in the world may be able to achieve speeds that are 20% faster than previously thought, according to reports.

During a recent experiment using 16 quadrature amplitude modulation (QAM), the Microsoft- and Facebook-owned and Telxius-operated 4,000-mile MAREA undersea transatlantic cable reached a record transfer speed of 26.2 terabits per second (Tbps). This is a 20% improvement over the original 20 Tbps rated capacity for the cable's eight optic fibers. The combined fibers had a total theoretical capacity of 160 Tbps.

The MAREA cable runs between Virginia Beach, Virginia, and Bilbao, Spain — both popular locations for new data centers.

According to experts, the news is significant for two specific reasons. First, the fact that the speed was achieved on an existing cable could mean future capacity upgrades may be possible without having the additional expense of laying new and expensive cable. The second reason is that speeds were achieved on a cable that spans a great distance.

Yet, experts caution that it will be some time before those speeds become common. While 20 Tbps transfer speeds were thought to be theoretically achievable, the MAREA’s average transfer rate is currently just 9.5 Tbps, which suggests that roadblocks still exist.

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