Even though SATA II drives are rated at 3.0Gbps, then NEVER come close to saturating that bandwidth!
My best HDD only gets read/writes near 100MB/s (or 1.0Gbps). Far cry from the SATA II bandwidth rating!
Now SSDs vary, but an Intel X25-M 80GB is rated at read/writes of 250/70, and this is very close to what they actually give!
Yes, writes are slower on an SSD than HDD, but once the OS installed, READS ARE WHERE IT'S AT!
Once you go SSD, you'll never go back!