There is a known issue with Core2 CPUs, the next UWN includes the following
Intel Core 2 CPUs Have Been Affected By An Annoying Linux Kernel Bug For 5+ Years
Michael Larabel reports of a fix for Intel Core 2 processors’ system stalls and slow boot in the 6.14 kernel. The reason for the long standing affect is disclosed with the fix expected to be back-ported to stable series soon.
See Ubuntu Weekly Newsletter Issue 881
Ubuntu 24.04 LTS currently uses the 6.8 kernel (if using GA), or 6.11 (if using HWE), with Ubuntu 24.10 using 6.11; neither of which have the fixes yet mentioned in that article (as not security related; I’d not expect it until 24.04 upgrades to the 6.14 HWE kernel if you’re using HWE; 24.10 users will get it when they release-upgrade to 25.04 where the 6.14 HWE kernel will come from)
Ubuntu flavors all use the standard Ubuntu base at boot; the differences beyond that are mostly superficial or set by your install media (ie. flavor media may install with either GA or HWE kernel; controlled by ISO used to install), thus I’d expect them to be essentially identical (some flavor ISOs allow a snapd free install which may make boot & login a tad faster, but its still a minor difference in my opinion)
If what you’re talking is something else though (either related to a config or other package option) you were vague, I felt, with details so I’ve responded based on a Core2 detail in your paste which is a known value.