I would check your terms because they're quite opposites, so you might be wondering about terms more closely related.

譜代 fudai means hereditary vassals. 大名 daimyō are defined in the Edo period as clans with realms of at least 10k koku. So fudai daimyō are the families who had directly served the Tokugawa a long time, usually at least before Sekigahara, though a handful were added later on. They either already started out with or awarded significant domains and were above the regulation lower boundary of 10k koku needed to qualify for a daimyō. They were the most influential families in the Shogunate administration, pretty much monopolizing the positions of 若年寄 (wakadoshiyori junior elders) and 老中 (rōjū elders). Some kind of surviving law code/constitution/order/will from the really early Edo specifically states that the Shogunate's affairs are to be administered by people picked from able descendants of these families, and that due to their loyal service the Shogunate is not to let these families disappear no matter what. According to Totman there were 91 fudai daimyō clans in 1615.

御家人 gokenin on the other hand are direct vassals of the Shogunate, ie those who did not have a realm of at least 10k koku and therefore were not daimyōs. Similar to the 旗本 (hatamoto under-the-banner) they were low-mid class warriors in direct employment of the Shogunate, but unlike the hatamoto they could not get an audience with the Shogun in person. They could come from fudai families, but were by definition not daimyōs and were generally politically unimportant.