SoftIce (v3.1) Memory Searching problem ...

Can someone advice me how I should search memory for some value ? I am using "s 0 l ffffffff 'value'" but I often get freeze computer (neverending searching - or searching is very slow and I cant cancel it) and can do nothing but reset. Is there way how can I get memory range which is used by program I am "analyzing" (prob newbie question - sorryz). Or maybe there is better tool for memory searching? Thx in advance.