Higher than the mentioned frequencies might be possible, however achieving them will require the voltage to be raised to a point where the power efficiency is long gone and the life time of the silicon is reduced. At frequencies beyond the inflation point (3.9GHz in the chart) the cost of the last 100MHz in frequency can easily be > 25% increase in the power consumption.
With the tested samples 4.1GHz could not be achieved even at 1.550V despite 4.0GHz was deemed stable at 1.375V, which is already high but still well in the realms of sustainable.
With Raven there is also another aspect, which is not present on Zeppelin: Unlike Zeppelin, Raven uses conventional TIM (instead of indium sTIM) between the core and the heatspreader. The conventional TIM used on Raven isn’t the only factor which affects it’s thermals either. Due to the extreme thinness of the Raven die, the heatspreader used for Raven AM4 APUs has been redesigned. Normally the contact surface inside the heatspeader is perfectly flat. The heatspreaders used on Raven have a “hump” inside them, which allows the heatspreader to make contact with the die itself. Without the “hump” the heatspreader would only make contact with the SMD components located around the die, which are standing taller than the die itself. The “hump” adds an extra 0.5mm to the heatspreader thickness and therefore increases the thermal resistance of the heatspreader as well.
Despite the Raven's slightly larger die size, the temperatures are still significantly higher at the same power dissipation and cooling. Even at a modest 65W power dissipation the CPU cores can reach excess of 70°C temperatures.
An aftermarket cooler is definitely recommended at least for the 2400G, especially if there is any plans to overclock the chip. 2400G at the stock configuration is already somewhat bound by the default 65W power limit and the chip can easily dissipate up to 120W of heat when it is overclocked to the typical maximum figures.
https://i.imgur.com/dMwRtn9.jpg
Some ballpark 3D performance figures, based on my own testing: RX 550 is around 22% faster and the RX 560 around 68% faster than a stock 2400G APU.
When the 2400G APU is overclocked to the typical maximum figures (1600MHz engine and 3400MHz DRAM) it’s performance is almost identical to a stock RX 550.
- 2400G at stock: 1240MHz engine, 2933MHz DRAM (3236 in 3DMark Fire Strike)
- 2400G at a typical max OC: 1600MHz engine, 3400MHz DRAM (3960 in 3DMark Fire Strike)
- RX 550 at stock: 1210MHz engine, 7000MHz (QDR) DRAM (3955 in 3DMark Fire Strike)
- RX 560 at stock: 1210MHz engine, 7000MHz (QDR) DRAM (5430 in 3DMark Fire Strike)
If you are unfamiliar with some of the terms used, please check the original Ryzen: Strictly Technical write-up.