how do i check what chip i have?

[t0m]

yeh im a newbie to this so try not to flame me too much and i'l prolly get things wrong.

i baught a ps2 with a chip a year and a half ago, its been working fine it boots psone copies and ps2 rips perfectly, but i copied my first DVD game the other day with nero express and there were no errors, but i cant boot it. i dont know whether this is the game/boot method/chip that wont let me boot it. the game was GTA3 and i used DVD-X to boot it, by loading DVD-X up and swapping the disc when it was fully loaded then press start. it didnt work tho. so now i want to know exactly what chip i have actually got, ive opened up my ps2 before so im pretty confident i wont mess anything up if i open it up again, i just need to look for it right? where will it be and how, just by looking at it, will i know what chip it is?

thank you in advance for your help.