This may be a performance problem, not the frame rate.
Actualy when i ran Winter Blast on my old PC 900 Mhz 128 Mb RAM, its kinda slow though

Well, my main ways to keep the performance :
- small game resolution (my standart is 320x240, max 480x360)
- turn off actor's activity if out of vision
- avoid giga cloning (more than 500 clones)
For more tricks, looks here
viewtopic.php?f=5&t=7310