RADEON X1800 XL
The less powerful, XL-indexed RADEON X1800 uses the same PCB as the senior model but differs in the design of the cooling system and the clock rates. Like the RADEON X1800 XT, the RADEON X1800 XL is equipped with a Rage Theater chip.
This graphics card uses Samsung K4J55323QG-BC14 chips (256Mbit, 1.4ns access time, 1.8V voltage, 700 (1400) MHz rated frequency). The RADEON X1800 XL clocks its memory at 500 (1000), i.e. below its official rating. Eight 256Mbit chips give you a total of 256 megabytes of memory. Like on the RADEON X1800 XT, the memory chips are located on one side of the PCB only; there are no empty seats on the reverse side of the PCB. So, unlike NVIDIA with its GeForce 7800 GTX, ATI varies the amount of graphics memory in its two top-end models by replacing 256Mbit chips with 512Mbit ones.
This R520 chip is a little older than the one we have seen on the RADEON X1800 XT. This one is dated the 32-th week of 2005. We suspect it to be an earlier revision of the R520 chip, unable to work at frequencies above 500-550MHz.
The cooling system differs from the one installed on the RADEON X1800 XT. It is based on two U-shaped heat pipes that evenly distribute the heat from the GPU-contacting base in the thin copper ribbed section. The memory gives its heat out through the aluminum casing. The straight-bladed fan takes air from inside the PC case and drives it through the ribbing section and back into the system case. In fact, the air stream cools just the heatsink on the power circuit elements.
Using the heat pipes ATI made the cooling system of the RADEON X1800 XL fit into one slot, but the fan is probably noisy. We already met such a fan on the PowerColor X800 XL graphics card and were not pleased with it (for details see our article called PowerColor X850 XT and PowerColor X800XL Graphics Cards Review ). Like on the RADEON X1800 XT, the cooling system is adorned with a picture of Ruby.