wan to ask if buy physical gold or silver in malaysia, which type is better for future to sell out ?
example PAMP suisse, Emirates, Scottdale

I've noticed CIMB's spread jump oddly during off hours to >8% then back to 3% during trading hours couple times.

Sucks to hear CIMB with errors, I'm too lazy to get to a bank during office hours... Be good to hear from others with experience.
You fell victim to their marketing of 6.4% as 6% and silver as well. If you look at:

https://www.publicgold.com.my

Taking today's rate of:
1. Gold 250g (48,629/45,712=~6.4%)
2. Gold 1kg (194,517/182,846=~6.4%)
3. Silver 1kg (2,954/2,600=~13.6%)

Don't just take other people's word for it - do your own calculations.