Not. Export at general: time depend on Mpixel (eg.: Megapixel / sec.) - larger pic takes more time. Masking, and stuff may also can add. NR: DP3 faster, DP XD2s slower (like double). And of course, general hardware performance → with Faster GPU (newer chipset, faster clock speed, faster VRAM bandwidth) is faster. I read in the forum some Export issues regarding export performance - however its not happen for everyone / every case. You can read in forum a lot of very fast export times. GPU VRAM amount more related with AI masking, DeeprimeRendering, Export NR type, etc.
At general, if not some relatively extreme export time come out, i not see any reason to compare export times. As its at general as-it-is (hardware). For fast computers is very fast, for dog slow Pc (like mine) is slower. I can tell, my slow PC with ancient 4GB GPU → 20Mpix Oly Raw + DP3 + Manual AI mask - Export takes approx 30sec (to Tiff)