The gDDR5 memory used on our test unit are Hynix H5GQ1H24AFR parts with T2C markings. These are rated for 5.0 Gbps at 1.5 V operation. AMD runs these parts at approximately 1.6 V. 
You can decide for yourself whether it is clever engineering, or a cost cutting measure. We’re going to raise MVDD anyway.
The default MVDD on our test unit is 1628 mV in 3D mode. You may use a 100k ohm potentiometer in the same position. Once again, remember to set the potentiometer to its full rated value prior to installation; reduce resistance for increased MVDD.
No over-current or over-voltage trip points were observed below 2000 mV MVDD.

MVDD Modification – With a Pencil
Owing to the relatively large value of the resistor used in the “loop,” it is possible to perform the MVDD Modification using a pencil.
The instructions have been detailed earlier in this article.