How to fix Matrix Platinum HD 7970 square artifacts
275This video shows how to fix the small square artifacts or graphical errors that show up in 3d applications and games known to affect a smaller percentage of these graphics cards.
The problem is that the matrix platinum comes factory overclocked with 1650Mhz @ 1.6V on the VRAM. The Hynix memory modules are rated to run at 1500Mhz @1.5V. Since they are overvolted out of the factory they may require additional heatsinks since 4 out of 12 modules are left uncovered by the uni-sink. Most of these chips can withstand being overvolted without cooling but there are some that do. The ones that do will occasionally show artifacts in games at stock settings.
This also applies to the newer Matrix Platinum R9 280x since it has the exact same cooling design but is less likely to encounter the vram artifacts due to running at 1600Mhz (6400Mhz effective) stock.
The VRAM heatsinks I used in the video are the Zalman ZM-RHS1. They are less than 0.25 in (6mm) tall but the clearance needs to be less than 4mm so I had to bend 3 out of 4 of the heatsinks to be able to fit the stock cooler back on. (Bend the heatsink fins using pliers BEFORE installing the heatsinks on the vram chips).
Note: Doing this sort of hardware modification voids the factory warranty. I do not take any responsibility for mishandling of electronic components which may result in hardware failure. If you do plan to follow this guide proceed at your own risk.