Better fps when UNDERCLOCKED, WTF?

[seumas_beathan]

So i decided to overclock my HD 5770 from 850mhz on the core 950mhz but i accidently just put in 95 which underclocked it to its minimum of 425. Interested to see what effected this would have on games I loaded up minecraft, only to see that the average fps had gone from about 70 to about 160

Anybody got any idea whats going on here, could it be that at standard speeds the gpu is an overkill for my e6750 at 2.66ghz

 

[dj1001]

you have a major cpu bottleneck. Use msi afterburner onsceen display to check you GPU activity. If it is not constantly at 99% with vsync turned off you have a bottleneck.

 

[seumas_beathan]

So i turn off vsync and what should i put the core clock to?

 

[seumas_beathan]

With vsync off and it at its standard clock speeds it is only using about 35-40% of the gpu? Is this bad?