Jumbo Frames and NIC's

[HEADRAT]

Hi,

I'm just fiddling about with the MTU size but my NIC's (in seperate machines) show:-

Realtek NIC

Jumbo frames
2KB MTU
3KB MTU
4KB MTU
5KB MTU
6KB MTU
7KB MTU

NVidia NIC

Jumbo frames
1500 bytes
2500 bytes
4000 bytes
9000 bytes

I'm not familiar with the notation on the Realtek NIC, what does a 3KB MTU equate to in old money, 1500 bytes?