[PD] GEM performance problem on ubuntu 64 bit and/or mac hardware?

[Matteo Sisti Sette]

Hi,

Is there any known serious performance issue with GEM on Ubuntu 64bit?
Or is there some known problem with this OS on intel macs?

A friend of mine has just installed Ubuntu 10.04 amd64 on her Macbook 
pro which has an intel core duo 2.4GHz processor.

She has tried a patch which plays 4 videos at the same time and she 
experience much worse performance than I do with the same patch and same 
videos on my intel core duo 2.1 GHz pc.

The only differences appear to be the hardware and the fact she is using 
64bit ubuntu while mine is 32bit.....

I'm not sure if the macbook may have a slower hard disk or a less 
powerful gpu, but the difference in performance is about a factor 2, 
it's huge.....

I know this is very little information but does this remember you of 
some known issue?

thanks
m.