AMD Radeon RX 7800 XT & RX 7700 XT Performance, Power Analysis & Noise Output

Part Analysis

AMD RX 7800 XT Part Analysis
GPU Navi 32 (5nm, 350 mm², 28.1 billion transistors)
RAM ICs 8x Hynix H56G42AS8DX-014 (250 MHz, 20 Gbps effective)
GPU Power Phases (VDDCR_GFX) 8x
Memory Power Phases   VDD_MEM: 2x
VDD_SOC Power Phases 2x
VDDCR_USR Power Phases 1x
Power Phases Monolithic ICs
14x Monolithic Power Systems (MPS)  MP86957 (70A, 100kHz to 3MHz Switching Rate)
GPU Phases Controller
Monolithic Power Systems (MPS)  MP2853 (up to 6x Phase native support)
Memory Phases Controller
Monolithic Power Systems (MPS) MP2856
Monolithic Power Systems (MPS) MP2856
Cooling Fans
2x  Delta Electronics AUB0812VD-00

Taking apart AMD’s reference card is not hard. The metallic backplate protects the card while helps in lowering its operating temperatures. Since I had limited time to deliver this review on time, I will only analyze the RX 7800 XT. The RX 7700 XT’s design is similar, though.

The black heatsink has four heatpipes, and its plate looks to be made of copper for better heat handling. The blue padding is of good quality, ensuring good heat transfer. It reminds me of the PUTTY 607 that XBOX uses.

Photos of the PCB’s front and back sides.

The Navi 32 GPU. TSMC Taiwan makes it using a 5-nanometer process. It has a die size of 350 mm², enough to host 28.1 billion transistors.

The GPU (VDDCR_GFX) is powered through eight power phases, while two power phases handle the VDD_SOC. The RX 7700 XT PCB’s main difference is that it has one VDDCR_GFX less.

Monolithic Power Systems (MPS) provides the monolithic ICs handling all power phases, and their model time is MP86957. Each can handle up to 70A, and the maximum switching frequency reaches 3 MHz. The VDDC_GFX controller is an MP2853, which supports up to six phases in total, so it has to have some help to control all power phases. The RAM’s voltage controller is a Monolithic Power Systems MP2856 controller. Another M2856 controller handles VDDC_SOC and VDDCR_USR.

The Hynix GDDR6 RAM chips can do 2500 MHz (20Gbps effective), and their model number is H56G42AS8DX-014.

The pair of cooling fans and their frame. The cooling fans are by Delta Electronics, and their model number is AUB0812VD-00.

My friend Igor (Igor’s Labs) was kind enough to share with me the 7800 XT’s PCB layout.

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *