I have same problem. Transfer large files 4GB+ sized files. Transfer is from one SATA 10K RPM drive to another SATA 10K RPM drive. Speed starts out fine until about the first 4Gb. Then rate drops steadily. CPU stays at about 100% for one CPU (have a Quad core i7 processor). Running Ubuntu 9.10.
I have same problem. Transfer large files 4GB+ sized files. Transfer is from one SATA 10K RPM drive to another SATA 10K RPM drive. Speed starts out fine until about the first 4Gb. Then rate drops steadily. CPU stays at about 100% for one CPU (have a Quad core i7 processor). Running Ubuntu 9.10.