If we believe a benchmark score at Nenamark, then Samsung is going to launch a new version of Galaxy Nexus with a processor bump. This is the first time, we are hearing about any upgrade to Nexus and it might be nothing. So, take it with a pinch of salt.
A new listing over at Nenamark benchmark database is showing a device named Galaxy Nexus with PowerVR SGX 544 GPU, which is different from the one in current version of Nexus on sale. Currently G-Nex comes with TI-OMAP 4460 with SGX 544 GPU and if this listing is true, Galaxy Nexus will need to have the next-gen TI-OMAP 4470 on-board to support 544 GPU.
TI-OMAP 4470 comes with significant improvements over 4460 and can be clocked till 1.8GHz.