The list prices of the i915PL and i915GL products were originally reported to be about 30% lower compared to the pricing of the i915P and i915G products. The assumption meant that the 915GL might cost around $27, while the 915PL might cost around $23, compared to $33 and $38 for i915P and i915G respectively, in the second half of January, 2005.More info at X-bit Labs
Intel launched i915GL and i915PL chipset

Intel silently launched two new chipsets; the i915GL and the i915PL. Both are cut-down versions without DDR2 memory support and with support for only 2GB memory instead of 4GB.