How to get a stable overclock sapphire hd 7950 oc boost vapor-x

Overclocking Boost HD Sapphire Graphics Graphics Cards
By See all their Tutorials
Here comes a little tutorial on how I overclocked my crossfire HD 7950 from Sapphire (the OC Boost Vapor-X).

Part 1 (pre BF4)

1. I Assured that I had a 750 watt PSU in place. At first I was using a 600W. Although I have not noticed any problems in crossfire with the 600 watt PSU I decided to upgrade to a 750 watt PSU. This happens to be the Corsair CX750M PSU. Not the best of the best, but till now it functions as expected.

2. Then I Upgraded my MBO from a Asrock Pro4 to an Asrock Extreme4. I did this because the Pro4 mbo lacks a second PCIE 3.0 slot.

3. I added another 8 gb of memory. So now I run 16gb of 1600mhz memory in dual channel mode (Corsaire Vengeance).

4. I upgraded to a 120hz gaming monitor (Benq XL2411T).

After these steps I was noticing a reasonable performance gain (About 15-20%). I hear you think that that is not so much. But in terms of FPS I went from about 50-80 to 60-90.

Now I wanted to take it even further. At first I wanted to OC my gaming PC only on stock voltage. This because I do not want to damage anything. I have to read even more on voltage tweaking to do it safely without wrecking my hardware. This is what I did:

5. Gave my locked CPU (I5-3470) an overclock to 4.0 ghz. This is possible through the Asrock Extreme4 mbo. This is the maximum OC for this CPU. If I want to take it further I have to upgrade to an I5-3570k. But that is not on my mind for now.

6. The next step that I took was to overclock the 2 HD 7950's. To do so I gathered information on this forum. I learned that the most important performance gain comes from overclocking the core speed of the GPU. In my case I ended up with 1150mhz on both the GPU's. I have done over an hour of testing with 3d Mark 11 and tweaking the overclock on the core by 25 mhz at the time. I went up to de max of these cards, 1200mhz, but that left the system unstable. So 1150mhz gave the highest score in 3d Mark 11. One of the tips from this forum was that I had o adjust the powerslider in Catalyst Control Center to +20% tot support +1100mhz on the core clock of the GPU. So i did and the system seems to be stable.

7. After adjusting the core clock on the GPU I started tweaking the memory clock. The base clock on the HD 7950's I own is 1250mhz (OC bios activated). Adding mhz's to the memory clock strangely did not improve the test result score in 3d Mark 11. So I ended my test with an overclock of 1150 on the core and 1250 on the memory.

8. Now I fired up Battlefield 3. Why this game? This is the only game I have played for over almost 2 years. I have tried other ones, but nothing seems to catch me as much as BF3. From of tomorrow I will be playing BF4 as much as possible. Looking forward to it. When playing BF3 I ended up noticing 80-110 FPS (on ultra, 1920x1080, 120hz). So I added another 5-10% FPS wise. While playing the game I added mhz to the memory clock speed by steps of 25mhz. I ended up with 1350mhz on the memory. Adding more mhz's to the memory clock left me with a pc freeze. So I decided to leave my overclock on the final 1150/1350 on both cards. My FPS gained another 20% (90-130 FPS). Which is the best performance on my gaming pc I have ever achieved.

The next steps are voltage overclocking and tweaking ingame settings. I have every setting on ultra so there I expect to get another performance gain on that aspect. When I am ready to start with voltage overclocking I will post my findings again.

Tanx for reading and use this info to your advantage!

Part 2 (BF4 released)
Today BF4 is released in Europe and I played a few TDM games just to get te feeling. I have to say that my OC as described in part 1 is suprising me..:-)

The following screenshots are taken this morning with fraps:

My video settings:

My highest FPS:

Some other shots:

I think the results are pretty impressive. I do not know what FPS I will hit when playing 64 players on an conquest large map but I will find that out very soon.

The conclusion of this tutorial is that 2 HD7950 in crossfire running on stockvoltage and within the OC possibilities of the catalyst control center and the 13.11 beta 7 drivers BF4 performs really well.

Part 3

So after several days of playing BF4 and some newer AMD drivers I wanted to update this tutorial. I installed the latest AMD 13.11 beta 8 drivers (the newest last week) and found out that it had a huge impact on my FPS (it dropped to 60-80 fps with the same overclock on my sapphire crossfire cards). I do not know why, but it happened, so I decided to go back to the beta 7 drivers (al of a sudden FPS was still low??). This weekend a newer version of the beta drivers appeared (the 13.11 beta 9.2). I also upgraded my CPU to a 3570k (my former cpu was a 3470) and my PSU from the Corsair CX750M to a XFX pro 850 core edition (second hand). After OC-ing the CPU to a stable 4.5ghz (on an air cooler, the cooler master 412s) and adding the extra power I now have my system running BF4 with an FPS of 100-130 with some ups to about 150 fps and once in a while dropping to about 95 FPS. But overall a nice and stable gameplay.

Although I have a reasonable FPS I can't wait to see what happens when the Mantle drivers appear.