Closer Look at AMD Radeon HD 7770 GHz Edition and Radeon HD 7750
The pair of reference cards from AMD came to us without their official packaging and accessories. That’s often the case with reference samples although the Radeon HD 7770 and HD 7750 are both available in different versions from all the major brands by now. Our cards look like this:
They are very small, the HD 7770 being 211 millimeters long and the HD 7750, a mere 168 millimeters. The latter has a single-slot design even.
The Radeon HD 7770 GHz Edition is equipped with one dual-link DVI-I output, one HDMI connector and two mini-DisplayPorts. There’s a vent grid above them to exhaust the hot air out of the system case.
As for the Radeon HD 7750, it has one dual-link DVI-I, one HDMI and one DisplayPort. It has neither power nor MIO connectors which are available on the Radeon HD 7770 GHz Edition.
Let’s take a look at their PCBs:
The HD 7770 GHz Edition employs a 3+1+1 power system with 3 phases for the GPU and 1 phase for the onboard memory. The Radeon HD 7750 is simpler in this respect, having only 2 phases for the GPU. The HD 7770 GHz supports software-based GPU voltage management whereas the HD 7750 lacks this feature.
The two 28nm Cape Verde chips have identical markings down to the date of manufacture (51’2011):
The clock rates comply with the official specs: 1000 MHz for the Radeon HD 7770 GHz Edition and 800 MHz for the HD 7750. The clock rate is lowered to 300 MHz in 2D mode. The rest of the specs are listed in the table above.
Each card comes with 1 gigabyte of GDDR5 memory in four chips from Hynix Semiconductor:
Labeled H5GQ2H24MFR T2C, the chips have a rated clock rate of 5000 MHz, which leaves some room for overclocking since each card clocks its memory at 4500 MHz by default. The memory clock rate is reduced to 600 MHz in 2D applications. The memory bus is 128 bits wide.
Our GPUs turned out to have a rather low quality level: 72.7% for the Radeon HD 7770 GHz Edition and 74.3% for the Radeon HD 7750.