500203-561 - HP 4Gb PC3-10600R 1333Mhz DR x4 CAS-9 (256Mx4) DIMM - Intel

RAM speeds were traditionally listed in MHz (e.g. DDR4 3200MHz or DDR5 6000MHz). Today, the industry standard is MT/s (megatransfers per second), so you'll now see speeds shown as DDR4 3200MT/s or DDR5 6000MT/s.

What does MT/s mean?

MT/s measures the number of data transfers a memory module can perform each second, making it a more accurate way to express RAM performance.

In practice, a module labelled 3200MHz is the same speed as 3200MT/s - only the terminology has changed.