1) The older GK107: http://www.techpowerup.com/gpudb/81...rce-gt-640.html

128bit Bus (28.8 GB/s bandwidth)

810 MHz Core
TMUs: 32
ROPs: 16
PCI-e 3.0 16x

2) The newer GK208: http://www.techpowerup.com/gpudb/23...-640-rev-2.html

64bit Bus (40 GB/s bandwidth)
1046 MHz Core
TMUs: 16
ROPs: 8
PCI-e 3.0 8x

看規格表效能應該還是半斤八兩