My Radeon 5770 Hawk is getting pitiful overclocks

Question

I bought a 5770 hawk so I could overclock it far. But, my card barely overclocks. Is this normal? The core can only get up to 910MHz stably on stock voltages. The stock clocks for the card is 875MHz. Is this normal? I can overvolt it to 1.25v and get up to 945MHz, but when people overvolt it that high, they normally get to 1GHz, and those are on the normal reference models. The Hawk is supposed to overclock like crazy.
The stock voltages of the card also seem to be higher than most cards, it is at 1.2v instead of the normal 1.125v that I usually see for most 5770s.  I tried to put the clock and voltage settings back to reference levels(850MHz/1200MHz @ 1.125v) and it wasn't stable under OCCT. Does this mean anything? If my gpu isn't stable under reference clock rates, no wonder it can barely overclock.
Can there be something wrong with my mobo or psu or something preventing higher overclocks? I'm using OCCT with error checking enabled to check the overclocks. Can that be a reason why it is not getting as high? Most people only use Furmark and visually check for errors, even though when you do that you easily can miss dozens of errors that are not visible to the human eye.

Answer 1

I know a lot of people are going to give me hell about my psu, since I have recieved hell about it many times in the past on internet forums, but just to let you guys know, I closely calculated everything, looked up tons of articles, and spent weeks looking into it before I made my purchase and I'm 100% sure that my psu can easily handle my system.
My system is a Dell Studio XPS 435MT.
It comes with
i7 920
4GB DDR3 RAM
1 640GB HDD
ATi Radeon 4850
1 DVD drive
1 Case Fan
360 Watt Delta Inc PSU
Before you goes go in on the Delta brand of the psu. Rest assure that they make quality units. They are the guys who make Antecs Earthwatts PSUs and their Signature psus. And they also make a lot of psus for companies like Dell. Johnny Guru reviewed a few Delta psus and he says that they make quality units. The psus they make for antec Earthwatts line are better than the PSUs Seasonic made for Antec.
Now the psu has lasted for over a year with the Radeon 4850. The radeon 4850 nearly 50% more energy than the 5770 Hawk
http://www.techpowerup.com/reviews/MSI/HD_5770_HAWK/28.html
These results have also been confirmed with various other Radeon 5770 cards from many other review sites. So if it works with the 4850 for hundreds of thousands of people with the same Dell model, it will work for the 5770 which consumes a lot less energy. Other people with the same Dell model have said that their systems used only up to 290Watts when under full complete load, and this is with the 4850 that draws way more energy than my 5770. And they measured their energy from the wall sockets which means that the actual energy the psu is supplying is less since you have to factor in psu efficiency. My system despite the unusally small psu is more than enough to power my system. 
My power supply can supply 15amps on the 12v1 rail and 16 on the 12v2 rail. It can supply a max of 300Watts or 25amps when both are being pulled from at the same time. Under a normal game the 5770 uses 6.66 amps from the 12v rails, and under Furmark it uses 9 amps. My psu can supply more than enough energy to my gpu even with the i7 which uses up to 10 amps from the 12v rails.
Now, when overclock, energy usage increases. Yes that is true but it only goes up a relatively small amount.
http://forums.atomicmpc.com.au/index.php?showtopic=264
With a 6% increase in clock rate, power consumption goes up by only 4%(When not overvolting). This can also be confirmed by many other review sites. Overvolting does increase power consumption by a large amount if you overvolt too much, especially in conjunction with overclocking.
http://www.xbitlabs.com/articles/video/display/gpu-power-consumption-2010_4.html#sect0
http://ht4u.net/reviews/2009/power_consumption_graphics/index11.php
But if you be easy on the overvolting, you can overvolt and not raise the power consumption through the roof.
I will never overvolt my gpu above .05 higher than the stock. I was able to overvolt my 5770 from 1.2 to 1.25v. That is around a 4% increase in voltage.
http://forums.techpowerup.com/showpost.php?p=1858205&postcount=1
This also shows that the power usage of a system with a 5770 doesn't go above even 250Watts when running OCCT, and this is when overvolted and overclocked a lot.
The only way for my system to even come close to 80% capacity of my psu, I'd need to be running Prime 95, and OCCT at the same time, and even then my system can handle that just fine. I've run occt for a long amount of time and I didn't get any power issues.