CPU upgrade on Dell:T3500 and a couple questions

[Rodney Doe]

I have a Xeon W3565 CPU, @3.2Ghz , and I don't really understand some things. Well, most things. It seems there are some six and eight core CPU's that will fit in my socket.

Do more cores, at the same clock speed mean better performance?  Also despite reading and reading and reading I am still confused on what RAM is best for gaming.

I have 16gigs of Kingston PC3-10700, not sure if it's ECC. Is there a faster RAM option open to me? Every answer I find seems to confuse to bring up two more.

I have to say after solving some cooling issues and getting a GTX 750ti ( already am looking to get something more future proof ) I am happy with it on the whole. The HDD has 16,000 hours on it so I will eventually have to upgrade everything. It's kinda overwhelming.

The only issue that is chronic and won't go away is the occasional fit it has where it won't boot because of a "cage fan failure" errors. It's really a pain in the ass. I replaced the front fans to no avail. Then I found out that there is a proprietary Dell hard drive cage with fan that didn't come with the PC because it only has one HDD. Can I assume the original config. for this PC had the extra HD caddy and fan and now that it's gone and not detected is the reason I am getting this occasional but chronic error?

Any other suggestions or comments are welcome.

[Droidbot]

Clockspeed > Cores in this situation. Faster RAM doesn't mean much for your configuration. Old WS CPUs are still able to kick ass in modern games with modern GPUs. 

The cage fan failure I've got no idea about, ask on the Dell forums or something similar.