[syslinux] Very slow download with pxelinux > 4.07 on specific hardware

[Eric PEYREMORTE]

Hi there,

We had to setup a pxelinux on a new server (windows 2012) and used the 
latest release of pxelinux 6.0.2.

Everything went ok on my first client test machine : dell optiplex 740. 
Pxe was really fast (vesamenu with large background image was appearing 
in less than 3 secondes)

But on different client machine i got different results :

On optiplex 790 (core i5 with intel 82579 nic) and 380 (core 2 duo with 
bcm 57xx), it takes 1 minute for the menu to appear.

On  optiplex 7010(core i5 92579lm), it is as fast as with optiplex 740.

At the beginning i thought it was because my newer machine were on an 
efi bios, but the 7010 is too and i have no problem(i always use legacy 
boot).

With pxelinux 4.0.7, everything is running smooth. I think i'll stick 
with this version. But i think i'm loosing some interesting features...

Any clue ?

-- 
Cheers,
Eric