MI25 is a Vega 10 (same as Vega 56/64) and the MI50 is Vega 20 (same as Radeon VII). CDNA is just a Vega variant too, you'll see that MI25/Vega 56/Vega 64 are all gfx9* generation hardware just like CDNA1 and CDNA2 [1], while later RDNA cards are gfx10* and gfx11*.
But, what difference does it make? Nvidia also shipped the same _architecture_ for their datacenter and consumer cards for quite a few generations back then (e.g. Pascal), though typically not the same die. Whether they reuse the same architecture or not, they had a product that they marketed as enterprise/datacenter cards. The buyers don't care if it's a rebranded consumer card or not as long as it works well - see the Nvidia L40S (uses AD102 - same as RTX4090 [2]) which is very popular in inference.
Not to mention, with GCN, AMD made an explicit bet on unifying their architecture for compute & graphics. They bet on being able to supply both the consumer and datacenter markets with the same silicon by coming up with graphics hardware that was quite compute-heavy (hence why AMD consumer cards were stronger against their Nvidia counterparts until the Ampere generation or so).
But, what difference does it make? Nvidia also shipped the same _architecture_ for their datacenter and consumer cards for quite a few generations back then (e.g. Pascal), though typically not the same die. Whether they reuse the same architecture or not, they had a product that they marketed as enterprise/datacenter cards. The buyers don't care if it's a rebranded consumer card or not as long as it works well - see the Nvidia L40S (uses AD102 - same as RTX4090 [2]) which is very popular in inference.
Not to mention, with GCN, AMD made an explicit bet on unifying their architecture for compute & graphics. They bet on being able to supply both the consumer and datacenter markets with the same silicon by coming up with graphics hardware that was quite compute-heavy (hence why AMD consumer cards were stronger against their Nvidia counterparts until the Ampere generation or so).
[1] https://gcc.gnu.org/onlinedocs/gcc/AMD-GCN-Options.html
[2] https://www.techpowerup.com/gpu-specs/l40s.c4173