I compared the 2 speeds on my usual PC. Don't consider this an accurate benchmark but rather some additional info. The RAM in this PC is not the only bottleneck.
Tested RAM
- Corsair Vengeance 2x8GB kit 2666MHz CL16
- Corsair Vengeance 2x8GB kit 3200MHz CL16
Setup
Motherboard: ASRock B550M-HDV
CPU: Ryzen 5 5500
GPU: RX 9060 XT 16GB driver 25.8.1
Cyberpunk 2077 storage: P3 Crucial M.2 1TB
Game settings: fully custom, around high settings, no RT, no frame gen or upscaling, no AMD "enhancements" in Adrenalyn
SAM enabled
Usual background apps: qbittorrent, LgHub, MSI afterburner, File explorer, Notepad
Tuning
CPU: -20 on the curve, +200 clock
GPU: -65 mV core, +250MHz memory, +10% power limit, -200MHz core
Results
In game benchmark
2666Mhz
3200MHz
Standing still outside the Glen apartment
Recorded using MSI Afterburner for 10 minutes, using their benchmark tool.
2666MHz
3200MHz
Conclusion
The difference is massive, at +15 FPS average, +12 FPS 1% lows and +10 FPS 0.1% lows in the stand still test.
The difference would probably be even larger with a more powerful CPU and GPU, as the ones I have are hovering around 75% and 87% usage respectively in the stand still test.
I think the biggest difference the 3200MHz RAM would make is in action when usage spikes occur, so this upgrade is very significant.
The prices are nearly identical for these 2 kits. There is no reason to buy the 2666MHz even on a tight budget.