IBM BlueGene's compute card is a fancy name for their CPU boards. A compute card hosts CPU (SoC) and a number of DRAM chips. First we got a BlueGene/L compute card. Eventually we got another set of BlueGene/L, BlueGene/P and BlueGene/Q compute cards.
BlueGene/L Compute Card consists of two processor chips and 18 DRAM chips.
The DRAM is a standard DDR SDRAM from Samsung with P/N K4H511638B-TCCC (32M×16).
There are no termination resistors on the memory bus.
There are another set of DRAM patterns on the back of the Compute Card.
Two connectors with dimension of 6-by-18 (108-pin) connect the card to the
rest of the system.
A conventional heatsink is glued on top of the compute chip.
Three generations of BlueGene Compute Cards.
The heatsink is glued to the chip on BlueGene L and P.
The BlueGene/L compute card pictured here have all DRAM soldered. The one that I got another day did not have them.
A heatsink is fixed to the BlueGene/Q Compute Card using six T10 screws.
Blue TIM is visible.