Can a Radeon R9 270x run 4k?

Generally r9 270x supports 4k60Hz mode, but supported resolution varies by GPU model and board design.

Is AMD Radeon R9 270x?

The R9 270X uses the same chip as the older Radeon HD 7870. Curacao, former known as Pitcairn, is based on the GCN architecture and offers 1280 shaders, 80 TMUs and 32 ROPs….Power Consumption.

Manufacturer	AMD
Core Speed	1050 MHz
Memory Speed	5600 MHz
Memory Bus Width	256 Bit
Memory Type	GDDR5