Lolol I actually take H3 Chem rn and having As. Promos grade was
AAAC (BCME 4 H2s) but wow H3 Chem is on an entirely different
level. While I've also maintained 95th percentile or so in Chem,
I'm struggling with H3. H2 prelims I scored an A, H3 I scored the
equivalent of a E LOLOL (I have to admit I wasn't prepared at all,
only managed to do 3.5 qns out of the 5 I'm supposed to do). The
gap between H2 and H3 is LARGE. I was actually advised to not take
H3 if I'm not confident in pulling up my econs grade... which is
why my econs is suffering rn haha.
However this is with knowledge that I'm applying for UK
medicine, which pretty much only looks at their specific UK med
test + BC (+ third science subject aka M) + H3 if any, so I can
sort of throw away E/GP (anything C and above is
acceptable).
Edit: It's essentially going to be very busy and hectic if you
want to score As in 6 core subjects and H3. If you're the type to
work hard, consistently (I'm not lolol) then go ahead. External H3s
are usually better. I know a friend who also takes PCME (promos
AAA/B) and he's doing VERY WELL rn (although he took external H3
physics).