PowerColor RADEON 9800 PRO 128MB
PowerColor RADEON 9800 PRO is a modern graphics card with a faster graphics chip. R350 VPU (RADEON 9800/9800 PRO) is in fact a slightly modded R300 (RADEON 9700/9700 PRO), particularly it works at a higher frequency and uses higher-voltage power. No wonder then that R350 consumes more power and generates more heat than R300. So the VPU voltage regulator in RADEON 9800 PRO reference design deserves such honor as a separate heatsink on some field transistors. The cooling system changed, too, as the heatsink area became larger and the fan acquired an elegant twist in the blades (to produce much more noise, to my opinion):
Nothing happened to the graphics memory. The chips still have no heatsinks. Under workload, they become much warmer than the memory on RADEON 9700 based card because of their higher frequency and voltage. Let’s see what we can do under such unfavorable conditions.
The design of PowerColor RADEON 9800 PRO differs from the design of the previous card, although all voltage regulators are based on the same chips. So I won’t repeat myself but will just show you a few snapshots with those regulators and places where I put additional resistors:
Note that the nominal voltage of the graphics processor in PowerColor RADEON 9800 PRO is about 0.2V higher than of RADEON 9700! The nominal voltage of the memory chips was also higher by this card. Besides that, VDD of the memory chips is balancing at the very limit of the acceptable voltage range as recommended by the manufacturer (Samsung and K4D26323RA-GC2A chips): 2.96V against the acceptable maximum of 2.94!
This high voltage of the internal circuitry is probably meant to provide stability at high nominal frequencies and under unfavorable conditions, or maybe this is a step towards overclockers?
Nominal Voltage, V
Reduced Voltage, V
The relative reduction of the VPU voltage was bigger than by the previous card: 17.7%. The memory chips, on the contrary, refused to be stable when VDD and VDDQ were dropped down by more than 14.6% and 19.4%, respectively. Obviously, the high clock rate makes it impossible to reduce the memory voltage any further.
So, now the graphics card is ready for our tests:
By reducing the voltage of the cooler from 12V to 7V we dropped its rotation speed from 3810rpm to 2650rpm. That’s a smaller reduction than in the pervious case, but the noise nearly vanished altogether. With less efficient cooling, the temperature of the graphics processor became 2-4°C higher, like by the previous card.
Voltage reduction proved to be of more effect by RADEON 9800 PRO than by RADEON 9700. The VPU was 6°C cooler in the Idle mode and 13-15°C cooler in the Burn mode. The temperature of the memory chips was even more sensitive to the voltage reduction becoming 5°C lower in the Idle and 30°C lower in the Burn mode!
That’s just an excellent result! The modded RADEON 9800 PRO card became both: cooler and quieter than the non-modded RADEON 9700-based card. That’s the more satisfying because PowerColor RADEON 9800 PRO is a more advanced and faster graphics card.
Now we will discuss a few devices with passive cooling systems.