I have Compaq V2000Z and try to upgrade memory to 1G. After researched few days from different websites, I found that manufacturers make different memory but with the same description KVR333X64SC251G & KTH-ZD7000/1G(ie. PC2700, 333Mhz, 200 pins, etc). It really confuses me how they produce so many type of memory with the same function. Do they make special memory only for certain type of computer?