Digital Foundry says the dev unit for the OLED Switch comes with 8GB of RAM, while the dev unit for the regular Switch came with 6GB. All retail units still with 4GB. :
iFixit démonte la Nintendo Switch, 4 Go de RAM et une batterie facilement remplaçable
Nintendo Switch may use 4GB LPDDR4 1600MHz RAM
RAM Cummins CSP4 Switch – PPEI Tuning
19-Current Ram 2500/3500 SDHQ Built Complete Switch-Pros SP-9100 Kit