YES, Virgin Media UK use the puma chipset in their cable modem. There is a Well known bug that virgin actually praise due to its ability to provide the rotten to the core company with plausible deniability if push comes to shove - of all culpability for slow speeds to its customers - so they maintain their modems with the chipset deliberately as a ruse.
Every single Virgin Media Hub 3 modem will have this issue, where single threaded network connections will suffer massive drops in speed. https://www.badmodems.com/
A quick search on google will give you thousands of reports and plenty of technical deep dives into what Virgin are doing to humans, the man at the top is in league with Barack Obama et'al, need we say more.
AVOID Virgin. Possibly one of the worse companies in the UK, bar none.
https://www.google.com/search?q=virgin+single+thredded+speed&btnK=Google+Search&oq=virgin+single+thredded+speed