
as you can see, you need a really great proecssor, 8GB of ram, and 2 or more GB of vram (I heard Doom 4 can even use 4GB if avaliable),
so, eliminate any notebook with the specs:
-less than 8GB of ram
-less than 2GB of vram
-get an notebook processor with the name ended with QM or HQ (That means, it's a true quad core processor)
-The gpu I cant say much, but something better than an AMD HD8870m is a must have