We're spinning this thread offtopic but it should be fine as long as you were not pushing too hard on Ryzen7. The mosfets themselves are the "normal" ones (Low RDS(on) Powerpak/etc) that will heat up after ~ 20A so essentially you don't have much thermal headroom. If you look at the datasheet , the limit at 100°C case temp is 40A on the SM4336 low side and 35A at 100°C case temp on the SM4337 high side. Without high airflow you'd have to rely on the junction to ambient rating which is much lower (16.2A for SM4337 and 18A at 25°C ambient for SM4336).
Typical Ryzen 5 hexcore overclocked is about 80A total ; Ryzen 7 is about 100A. There's been debate about how the mosfets are wired up and it is suspected that it is 4 phases in dual driver mode , rather than 4 doubled to 8 phases. If it's 4 in dual drive mode you don't reap the benefits of having phase interleaving (i.e. instead of 1/4 of the conduction loss , you get 1/2 since you have two mosfets in parallel for each phase) and the effective switching frequency is unchanged .
For Ryzen 5 you can essentially max it out at 4.1GHz , which is roughly the limit on water.
Edited by AlphaC - 10/18/17 at 10:05am