thumb AMD Radeon HD 6970/6950 Voltage Modification Guide
 

Our original AMD Radeon HD 6970 voltage modification guide verified, now updated to encompass all C200 PCB types. We show you how you can gain complete voltage control!

Same but Different
 
The AMD Radeon HD 6950 and Radeon HD 6970 graphics accelerators have been causing quite a stir – mostly for the former's ability to morph into the latter with little more than a BIOS update. The two are so similar, they even share identical power and thermal layouts in quite a few places.
 
We understand that VR-Zone.com readers don't stop at unlocking shaders, so we bring you this guide describing modifications that would coax the most out of your newly-purchased Radeon HD 6900 graphics accelerator. These modifications are designed explicitly for Radeon HD 6900 graphics accelerators built upon the C200 Printed Circuit Board (PCB) – verify this detail before you proceed.
 

Functionality Check
 
The ASUS EAH6970/2DI2S/2GD5 may not have made it in time for our review, but it came just as our Digital Multimeter (DMM) probes were starting to fly. We start off by putting it through a regular health check on our test system:
 
1 AMD Radeon HD 6970/6950 Voltage Modification Guide
 
Test Setup: Hardware
  • ASUS EAH6970/2DI2S/2GD5
  • ASUS P7P55D-E EVO (1301 BIOS)
  • Deepcool ICE WARRIOR
  • G. SKILL F3-17600CL7D-4GBPIS
  • Intel® Core™ i7-860 Processor
  • SilverStone Technology SST-OP1000
  • Western Digital VelociRaptor WD1500HLFS
Test Setup: Software
  • ATI Catalyst 10.12 Suite Windows 7 (64 bit)
  • CPUID CPU-Z 1.56 (64-bit)
  • Futuremark 3DMark 11 v1.01
  • Microsoft Windows 7 Ultimate (64-bit)
  • MSI Afterburner 2.1.0 Beta 5
  • TechPowerUp GPU-Z v0.5.0
To minimise potential interconnect bottleneck, PEG_CLK frequency was raised to 155 MHz.
 
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Mainboard and Memory details.
 
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Processor and Memory configuration.
 

Insufficient Interface Pressure
 
Earlier on, we noticed that a substantial amount of Thermal Interface Material (TIM) remained on the GPU IC when the Heat Sink Fan (HSF) assembly was removed from the Radeon HD 6900 graphics accelerators. Whether this is a deliberate decision made by AMD, is debatable – it hints of sub-optimal thermal contact in our books.
 
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Using cut-up ice cream sticks, we were able to increase thermal interface pressure  for a 3 Celsius reduction in (maximal) load temperatures. Loading was achieved via Futuremark 3DMark 11 v1.01, using looped Graphics Test 4 at "Performance" level. The comparison was performed at 950 MHz core clock, and 1450 MHz memory clock, using 45% fan speed.
 
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If ice cream sticks are impossible to find, you could of course chop up credit cards to size for the very same purpose.
 
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With the fan speed cranked up to 100%, it was possible to benchmark our sample at 983 MHz core clock and 1497 MHz memory clock; somewhat higher than most of the Radeon HD 6970 samples we have lying around. The ASUS "Full Aluminium Cover" appears to be working its magic alongside the increased thermal interface pressure.
 
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This short overclocking exercise translates to a pretty respectable P5744 score on 3DMark 11. Want more? Read on!