64bit platform is largely supported by Intel processors. With 64bit platform you have the ability to exploit most of the resourses of your system.
Actually most of the Intel processors have the 64Bit platform support. You just have to double-check it on the processor spec finder page to see if you have the Intel EM64T feature available on the specifice processor that you want to get. But I think it is available on all the Intel Quad Core processors. You can check it on the following link: http://processorfinder.intel.com/Default.aspx
Moreover the Intel EM64T is not enabled by default. To be able to use this feature you need to enable it in bios and also have a motherboard with chipset able to support 64bit platform.
You can also find more information about any Intel processors on the following page: http://ark.intel.com/
Well, in terms of benefits, Intel is ahead its competitor. I cannot comment further on this. It depends on many other factors to be able to tell you the real benefits. An advice is, Intel is better. Especially with the new architecture, the new Core i7 processors which outruns all other consumer processors.
More information can be found on this link: http://www.intel.com/products/processor/core2quad/index.htm?iid=prod_desktopcore+body_core2quad
Hope this will be helpful to you.