I have a little but important question

Anything that doesn't fit into other topics goes here!
I use old computer (laptop Fujitsu Lifebook P7010) and currently I don't have the possibility to listen in real time the tracks (if more than 4-5). I plan to change for a better laptop, but what is more important for this program - the CPU frequency or number of cores? I may bay i5 with 1,2GHz or i3, or Core 2 Duo with 3,4 GHz. This is a significant expense and I wouldn't be disappointed. Thanks for a suggestions.

p.s.
production with lmms :) http://www.jamendo.com/pl/album/99177
with hw best is always more :/ - so Core 2 Duo with 3,4 GHz would be a better longterm investment -but most important in respect to lmms is ofcause the soundcard! If you plan your new hw from a lmms usage perspective, you should look for hw with great soundcard. very few labtops comes with good soundcards, most have a tiny onboard soundchip, and no dedicated sound at all. I have no recomendation of any labtops in that context. Study the marked, and ask specific questions in the stores.

br -HNY
Thanks for your response - I have a question - whether the sound card participates in the generation of sounds and effects in LMMS?
Is if I export the tracks to the ogg file, the sound card is involved? I'm not plug the laptop into another device through linear audio output.
The soundcard is not doing the export. when you export a song the various generators and the wave they create is transscribed to a binary file. The program you use to replay these files can decode this binary code and use the soundcard to generate the waves
When you hear something - it is generated by the soundcard, but it will be difficult for you access the process if the sound from the card is crummy, as you make your project
You need a good or at at least a decent card
Br.
I think the discussion going in the wrong direction.
I have no problem with playing music on the laptop, my problem is 100% CPU load when I have opened the project.
So, listen to live changes is almost impossible (I must to turn off the other tracks but it does not always help).
Thus my question - whether for LMMS more important is the frequency or number of cpu cores.
The fact that both of these things are important is to me obvious.

Do compiling from source code should improve performance?
I have compiled version 0.4.11 but nothing helped and I had to go back to 0.4.5 because of ZynAddSubFx.