UPDATE #2: I now have a definitive answer to this question (whether you need new cables for 6GB/s SATA)… see below.
UPDATE #1: make sure to checkout the first comment to this post, as John posted some great additional info!
Q. Hello, I just got a super fast new Intel 510 SSD drive (and I have a C300 too). I’ve got a bunch of old SATA cables (back when SATA I/II 1.5 gbs 3 gbs was the max) and now I’m wondering if I need a special cable to take advantage of the 6 gbps speeds?!
A. Great question! You are in luck, your old SATA cables will be just fine! As long as they are good quality cables, there will be 0% speed difference, or in other words, “absolutely no difference in performance.” You do not need specially labeled SATA 6GB/s cables.
Specifically, here are the only differences I am aware of in the cable standard for the various SATA versions: some require a locking mechanism and some may have additional shielding (see comment #1 below).. However, older cables with friction fit WILL work just fine. We even have confirmation of cable compatability from the Serial ATA International Organization:
UPDATE #2 FINALLY A DEFINITIVE ANSWER:
Q9. Does SATA 6Gb/s require different connectors and cables to support the higher transfer speed?
A9. The same cables and connectors used for current SATA 1.5 and SATA 3.0 Gb/s implementations can be used to connect SATA 6Gb/s devices, although SATA-IO recommends quality components be selected to ensure data integrity and robust operation at the faster SATA 6Gb/s transfer rate. Keeping the existing SATA connector form factor enables SATA 6Gb/s to be designed into the same cost-conscious hardware architectures while minimizing infrastructure changes.
Source: SATA International Organization, SATA Revision 3.0 Specification [PDF]
Cool, now what we all knew from experience is now clearly stated in that PDF!
More supporting info below:
A quick guide to SATA 6Gbps – Pocket-linthttp://www.pocket-lint.com/news/23188/pocket-lint-quick-guide-sata-6gbpsExisting cables today will still be able to be used in the future with SATA 6Gbps, with no additions needed as it’s running from the exact same connectors. This removes the headache and additional learning curve, which often puts some people off with new technology.
Is a sata III cable different than a sata II cable? – Yahoo! Answershttp://answers.yahoo.com/question/index?qid=20101013125624AAP08xbAll SATA cables use the same electrical connector and wiring.
SATA 6.0 Gbps (they don’t like the SATA 3 term) mandates a locking connector at each end of the cable. Plain old SATA 3.0 cables will work just fine, as long as they don’t wiggle loose, however.
Serial ATA – Wikipedia, the free encyclopediahttp://en.wikipedia.org/wiki/Serial_ATA#Cables.2C_connectors.2C_and_portsThe SATA standard defines a data cable with seven conductors (3 grounds and 4 active data lines in two pairs) and 8 mm wide wafer connectors on each end. SATA cables can have lengths up to 1 metre (3.3 ft), and connect one motherboard socket to one hard drive.
Internal SATA cables are backwards/forward compatible between SATA I,II, and III devices at speeds up to 1.5gbs/3.0Gbs/6Gbs depending on your drives and controllers.
So, whatever your HD or SSD, all internal good quality SATA cables will be good to go and will NOT negatively affect your performance/speeds.