National Semi sold off their x86 lines quite some time ago to Via and AMD.
no. x86 has 4 companies holding licences and at least 5 who are allowed to produce x86 chips. POWER on the other hand - nobody but IBM is to allowed to design or make POWER chips. And Sparc? Oracle, Fujitsu and that was the whole range.
x86 is very non-monopolistic compared to those. And if you want to make a x86 chip you not only have to pay Intel, but AMD, Via and NatSemi to.
National Semi sold off their x86 lines quite some time ago to Via and AMD.
true, but they still have patents and licences. Nvidia has neither.
Also it depends on the features one wants as to who gets a piece of the pie. A x86 chip could only require a license from intel. A x86-64 chip however would require a license as well from AMD. One from Via would only really be required if you desired to implement such additional features like Padlock.
The other thing to remember as well is many of the patents are coming upon their expiry date. Anything found in a 486 and older has its patents expired already and patents for the pentium and MMX are soon to follow. Patents before June 8 / 1995 have a 17 year limit any thing after that has a 20 year limit.
copyright has no such short term expiration period ... and even if you can make a pentium mmx equivalent - what do you get? Some very slow, very outdated, very power hungry (in terms of performace/watt) CPU.
well, I don't think that you can patent something like SSE2/3/4. But you can have a copyright...