Video Memory

[slyexe]

Well I'm not entirely sure what exactly you mean by attack type. 

Royce is referencing different attack modes which hashcat uses. Such as Bruteforce, Wordlist, Hybrid, Rules, and whatever else you possibly plan on using for your cracking sessions. This changes the way hashcat distributes the load using VRAM, so as Royce said buying a card with 8GB VRAM is recommended for a wider range of attacks.