Ajax file uploads are very slow

[eluser]Unknown[/eluser]
Hi to all.

After many hours research on the internet, I have to post a topic here because I didn't find any good answer.

I have a form with file upload.
when using this form the normal way (I mean through a normal POST query)
it's very quick and works perfectly.

but when I use an ajax form to submit.
(i'm using this library now.http://jquery.malsup.com/form/)
I used several different ajax file upload libraries.
But when I apply them, it's veeeeery slow.
and sometimes the server throws me a 500 error.

My server is a hosting server that I posess. it runs about 10 websites on it.
and it's not my computer that's too slow sending the request.

It's just when I use ajax to send this form that the request takes so long.

Any Idea about this ?

P.S. I use the last version of CI, the 1.7.2

[eluser]darkhouse[/eluser]
That is a weird one, however, I recently started using uploadify and it's been working great.

[eluser]Queops[/eluser]
I use Uber Uploader (please google, it's on SourceForge), it's easy to install, versatile and works great. Uses PERL and PHP. (Variables that may restrict uploads are also explained on the documentation that comes with the download).