GMail’s interface certainly is speedy, but I don’t see Yahoo being any faster than Squirrelmail on my DH accounts.
If by speed, you mean there’s possibly something lagging the server you’re on–I guess that’s possible, but everything seems speedy for me at the moment.
You could contact support if you believe there’s an actual problem, unless you’re just referring to it as a sluggish front end.
Personally I like using an email client (The Bat!) over webmail, but on the few occasions where I use Squirrelmail, it hasn’t really bothered me.
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