I just had this issue and after a full week of crazy 10-20 second load times (especially on my home page) I finally bit the bullet and moved to BlueHost. Wow, light years difference! I strongly recommend to stop what you’re doing right now and quit messing with GoDaddy (you will never fix it) and just switch to someone else for your hosting. I wish someone told me this a while ago, it would have saved me so many hours on the phone and crazy re-installations, plugins and pulling my hair out.
Just so people know, I had the economy GRID Windows plan (had to use windows because I added a few ASP.NET pages). It was running WordPress 2.8 and Comicpress Theme. I actually had this same installation in a subfolder under a deluxe windows SHARED hosting plan with GoDaddy and the speed was actually ok. (But not nearly as fast as BlueHost). When I decided to add my ASP pages I moved it to it’s own hosting account and that was when it basically hit a brick wall. After a week of messing with it and their tech support, I thought that perhaps the problem was the cheap “economy” hosting plan. So I upgraded the account to deluxe… no difference.
GRID hosting will not make a difference. It really seems like the slow down is more database related (specifically with MySQL on GoDaddy) than hosting related. The only thing you can do is keep switching plans and pray that you eventually land on one of their hosting or database servers that aren’t too crowded yet (which is why I’m sure some other wordpress users don’t seem to have a problem).
Don’t get me wrong, I love GoDaddy and have a ton of ASP.NET/SQL Server sites hosted with them and they’re all fairly snappy and the price is incredible but when it comes to wordpress, I strongly suggest you move everything to another host and cancel this one. GoDaddy is always great about refunding you a pro-rated amount.