Did a bit more research - turns out not all 2070 Supers are the same -
https://www.kitguru.net/components/grap ... gb-review/
"On top of the fact that RTX 2070 SUPER uses the TU104 GPU, it’s also interesting that Nvidia’s specs claim it has ‘5 or 6’ Graphics Processing Clusters (GPCs). This is noteworthy because, for TU104, each GPC houses 4 Texture Processing Clusters (TPCs) – and the specs are very clear that RTX 2070 SUPER has 20 TPCs. So basic maths says the GPU should have 5 GPCs. So why the ‘5 or 6’?
Well, it turns out not all RTX 2070 SUPERs are made quite the same. They will all have 40 SMs (two SMs per TPC), but these may be spread across 5 or 6 GPCs – i.e. some GPCs will not be fully populated with 4 TPCs if you get a 2070 SUPER with 6 GPCs. Nvidia’s Rick Napier, Senior Technical Product Manager, told us:
‘We [Nvidia] sweep in a variety of ways, and as a result some RTX 2070 GPUs have 5 GPCs, and some contain 6. The performance difference between 5 GPC vs 6 GPC GPUs is negligible. Ultimately because we’ve outfitted the GPU with 20 TPCs and higher clocks, the RTX 2070 SUPER is on average 16% faster than RTX 2070.’"
Possibly something to do with this?