You should update the bios and make sure you have the latest drivers from nvidia.risc-vs-cisc

PS. GPU is HIS Radeon 4870 512

Today i started my pc and found out that i have hiccups while running windows vista . the HDD produces a sound just like a "click click" and then every thing comes to normal and then these hiccups come and go so frequently . The games are running with the same problem that when ever i fire a weapon or a new scene loads the PC just holds up for just a sec and then every thing works fine and then the same repeating sequence with frequent hiccups. All this wasn`t happening previously and the games worked fine . while writing this paragraph i ve had many hiccups but after waiting for some time what ever i write comes on screen . I changed my HDD but nothing got better.tried with sigle ram stick but the problem isnt gone . Any help guys

MY RIG:

ASUS STRIKER EXTREME

Q6600

Seagate 500 GB SATA ll

Corsair DDR2 XMS 800MHz