Prices of graphic cards are going crazy, should I buy a second card though?

A user on r/LocalLLaMA is considering adding a second GPU to their rig for local LLM inference but is deterred by the sharp increase in prices for AMD Radeon RX 7900 XTX and XT cards. The poster notes that while new RX 7900 XTX prices have risen to 1200€, used units are around 900€, and the budget-friendly RX 7900 XT starts at 700€.

• New RX 7900 XTX costs 1200€, while used prices are approximately 900€.
• The RX 7900 XT 20g is available for around 700€ as a budget option.
• Nvidia cards are described as prohibitively expensive, and mixing AMD RNDA 3 with other architectures may not work well with llama.cpp.
• The user seeks advice on whether an AMD RNDA 3 dual-card setup over PCIe 4x is worth the cost given current market conditions.