To be specific they're clocked 3x higher. 3DS to n3DS is a bigger processing jump than GB to GBC was.So does the 3DS-n3DS. The n3DS has twice the processors and they are also clocked higher.
GB to GBC
CPU clock: 4.19 MHz -> 8.38 MHz (2x)
RAM: 8 kB -> 32 kB (4x)
vRAM: 8 kB -> 16 kB (2x)
DS to DSi
ARM9 CPU clock: 67 MHz -> 133 MHz (2x)
RAM: 4 MB -> 16 MB (4x)
Storage: 256 kB -> 256 MB (1000x)
3DS to n3DS
ARM11 CPU: 2 cores -> 4 cores (2x)
ARM11 CPU clock: 268 MHz -> 804 MHz (3x)
RAM: 128 MB -> 256 MB (2x)
vRAM: 6 MB -> 10 MB (1.66x)
Storage: 1 GB -> 2/4 GB (2-4x)
PS4 to PS4 Pro
APU CPU clock: 1.6 GHz -> 2.13 GHz (1.33x)
APU GCN: 18 CUs -> 36 CUs (2x)
APU GCN clock: 800 MHz -> 911 MHz (1.13x)
RAM: 8 GB -> 9 GB (1.12x)
XBO to XBOX
APU CPU clock: 1.75 GHz -> 2.33 GHz (1.33x)
APU GCN: 12 CUs -> 40 CUs (3.33x)
APU GCN clock: 853 MHz -> 1.17 GHz (1.37x)
RAM: 8 GB -> 12 GB (1.5x)