ThinkPad T510 is using llvmpipe for graphics instead of Intel HD

My T510 was upgraded with a Intel Core i7 640M. I discovered that it's using llvmpipe instead of Intel HD for graphics, and I don't know why. I have everything related to Intel graphics & mesa installed on the system.

$ sudo lshw -c display
  *-display                 
       description: VGA compatible controller
       product: Core Processor Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       logical name: /dev/fb0
       version: 02
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom fb
       configuration: depth=32 driver=i915 latency=0 resolution=1600,2700
       resources: irq:27 memory:f2000000-f23fffff memory:d0000000-dfffffff ioport:1800(size=8) memory:c0000-dffff

$ DRI_PRIME=0 glxinfo | grep "OpenGL renderer"
OpenGL renderer string: llvmpipe (LLVM 13.0.1, 128 bits)