speed problem with gifs?

[theFlashWizard]

hi guys,
I'm trying to create a rollOver effect width css and javascript.
But it seems that all the buttons u once went over act strange.. they all react at the same time on the mouseOut on any of the links.
example:
http://members.lycos.nl/tut1/uploadbestanden/mouseOver05/

this is the javascript:
<script type="text/javascript">
window.onload = function(){
buttons = document.getElementsByTagName('a');
for(i=0;i<buttons.length;i++){
buttons[i].onmouseover = function(){
this.parentNode.getElementsByTagName('img')[0].src= 'mouseOverLeft.gif';
}
buttons[i].onmouseout = function(){
this.parentNode.getElementsByTagName('img')[0].src= 'rotateBack.gif';
}
}
}

</script>

a peice of the html:
<ul id="menu">
<li>
<img src="mouseOutLeft.gif" /><a href="#" title="Terug naar Home">Home</a>
</li>
<li>
<img src="mouseOutLeft.gif" /><a id="current" href="#" title="Onze oplossingen">Oplossingen</a>
</li>
</ul>

I zipped the complete example as well:
http://members.lycos.nl/tut1/uploadbestanden/MouseOverProblem.zip

can anyone explain what could by cousing this?
Hi guys & girls,
I seem to have a strange sproblem with mij animated gif's.

Firefox seems to run it much faster than Internet Explorer.
take a look at the example:
http://members.lycos.nl/tut1/uploadbestanden/speedProblem.htm

I also added a zipped example.
that includes 2 animated gifs. mouseOverLeft04 has a delay of 0,1 sec and mouseOverLeft05 has a delay of 0,05 secs per frame.
I made the gif's with Adobe imageReady by the way.

http://members.lycos.nl/tut1/uploadbestanden/speedProblem.zip

through the webmaster world forum I came to the following site:
http://members.aol.com/royalef/topten.htm

there I found this story:
Timing Delays too slow, too fast, not at all

Early versions of GIF Construction set said timed delays were in seconds. This was wrong. Timed delays are in 100ths of a second. A value of 100 equals one second. Navigator has a minimum overhead time which can be as much as 33/100 of a second. This means that slow Pcs that makes a request for a times delay will see a minimum of a 33/100 of a second between images. Some on Windows and MAC report a minimum of 10/100ths of a second between images. I believe this depends upon processor speeds.

so at least 0,1 secs a frame.

can anyone confirm this story? I ask it becouse it was last edited in March 1997.

sorry for the possibly strange english, I'm dutch

thanks beforehand
greetz theFlashWizard
Another strange thing is that I only see the problem in firefox and not in Internet Explorer.

thanx!