Rambus have 8ghz memory
Rambus introduced second generation of ultra fast xdr memories. While DDR3 memory works on maximal speed about 1200mhz, rambus xdr2 should work somewhere about 8ghz, and so bring much better performance for the best graphic cards and maybe ultra fast servers. They have some innovative technologies, for example microthreading, which allows to transmit only needed data, and not blocks as was before. Lets wait for what prices will those memories have.