Some of their marketing mentions no need for external DRAM, for example, from this CNX article[1]:

"One of the key reasons for the performance improvement is that RAM is self-contained without the need for external DRAM like other solutions. This decreases latency a lot and reduces power consumption."

Not sure how much RAM is included on the chip, but I'm also thinking in the tens of MB range, certainly not gigabytes.

[1] https://www.cnx-software.com/2020/10/07/learn-more-about-hai...