Doubt about Performance

[Ronan Lucio]

Hello,

Trying to keep the database and the application fast,
I´d like to clearify my mind about it.

1) Is a SELECT DISTINCT over 5,000 records a weight
    query? (Supposing it has about 20 different option the the
    DISTINCT key).

2) Is SELECT ORDER BY RAND() over 1,500 records
    a weight query?

I need to put these two queries in the first page of our site.
So, I´ve been worried if it can slow down our site in the
pics.

Thanks,
Ronan