Elon Musk personally debunked the rumor, saying the 1T parameters are not here yet, it's just a new 0.5T checkpoint, all for nothing.

ME News message: On April 18 (UTC+8), according to Beating monitoring by Dongcha, Grok 4.3 (beta) has been opened to users subscribed to the highest tier SuperGrok Heavy. On the 17th, users had already seen this version marked with an “Early Access” label in the dropdown menu on Grok.com. In the morning of the 18th, X user Mark Kretschmann posted that this version has 1T parameters, with a scale that is twice that of Grok 4.20, and a significantly longer training time as well. Later, xAI and Tesla CEO Elon Musk corrected this in the same tweet, stating that the current 4.3 (beta) is still a 0.5T model, just an updated training checkpoint, not the 1T new model people were speculating about