Yes, you need to multiply by 4. One general example, not for your GPU though. The effective speed of a QDR memory can be calculated as given below: QDR = Quad Data Rate or Quad-pumped:
QDR_Effective_speed = Real_speed x 4.
e.g., 1750*4 = 7000 Mhz. Its DOUBLE DATA RATE and Quad pumped. Not octo.
It's GraphicsDoubleDataRate6 memory/RAM. GDDR6 is Double Data Rate memory.
So the effective frequency is 2 x 2 x base frequency = 2 x 2 x 1750 = 7000 MHz.
Make a note. It is GDDR (Graphics Double Data Rate,), so the memory will communicate on both the leading/ trailing edge of its pulses. MSI Afterburner will show you effective memory speeds, but GPU-Z on the other hand will show you the actual frequency. Double that number and it will match.