Does collections only unlock the items you already have on you or does it unlock every item you have obtained from CM?

i dunno if i have the right stuff for the game because i lag like hell the system requirements says: AMD athlon 64 X2 Dual-Core 4000+ or better / Intel Core 2 Duo Processor 2.00Ghz or better At least 1.5GB or better for XP / 2GB or better for Window Vista/7 / PCs using built-in graphic chipsets, 2GB RAM is recommended ATI X1800 or better* / NVIDIA 7800 or better* / Intel 4100 or better* (*256MB Minimum Video Ram) *Shader 3.0 or better fully compatible graphics card. i have: Intel Core 2 Duo Processor 3.00Ghz 4GB RAM GeForce 8400 GS 512MB RAM is my computer better or worse then the system reuirements?