Hitting a wall OCing a Radeon HD6570 GDDR3

[IgnisVulpes]

First let me say hello since this is my first post here to the HWBOT forums even though I've been active in OC score submissions for the past 5 days or so.

 

I have a Sapphire Radeon HD6570 1GB GDDR3 video card that came stock 650/667. Now I've seen many submissions where people have gotten the core freq. anywhere from 675 up to 999 with only the stock cooling on this series of cards. My question is how? I don't mean how do you OC a card. I use Sapphire's Trixx overclocking program to OC but I seem to have this problem where if I take the core to 750-800MHz, which seems to be the average of the majority of submissions I see, while running a benchmark, using 3DMark2000 as an example, almost immediately it crashes and I get an error message saying, "3DMark could not initialize your 3D Accelerator. Try to downgrade your display settings. DirectX Error Message: DirectDraw->RestoreAllSurfaces : DDERR_SURFACELOST".

 

Highest I seem to be able to take it is 700MHz as I've tested it by looping only the helicopter test in 3DMark 2000 for about 2 hours straight with no crashes. Memory on the other hand I can go nuts with and even had it over 1000MHz without any issues.

 

So my question is why might this be happening when seemingly everyone but me can get a HD 6570 to 800MHz?

Edited February 16, 2014 by IgnisVulpes

[Calathea]

Quality differs, it's possible you have a bad ocing card. Also my guess is everyone close to 1 GHz core has volt modded it since stock volts can only take you so far.

[ObscureParadox]

It could also be that your particular model has a lower stock voltage compared to other models to help keep temps as low as possible. If the card is just a benching card and can be abused then I would suggest you look into volt modding the card to get the most out of it on air cooling. You will need a volt meeter, soldering iron, variable resistors and a steady hand. There is a volt modding section on the forum if you want help with your particular model or want to learn more about it.