I have the instruction set manuals and erratas for Intel and AMD processors.
There are some differences that Linux, for instance, worked around. The latest generation of compilers for Unix can generate code that will cause some errors when running on AMD. I have tried it and sure enough the return value when using certain math operations are different from Intel. These would, in all likelihood, never show up in a MS environment.
There are also 2 MMX instructions missing from the AMD code. These are emulated in software/firmware so they do not pose a non-operational problem. They are just slightly slower. They are also less likely to be used.
There are bugs in the Intel floating point code that are not present in the AMD code. Unfortunately, software that works around thse bugs cause problems with AMD. Again, if the software detects AMD versus Intel, it can be worked around.
Unfortunately, there are Unix's that do not detect AMD versus Intel and these particular operating systems have some problems with AMD. Linux has done a good job coding around the differences between the two companies processors.
Look guys, I am not saying AMD is bad, nor am I saying Intel is good. I am saying there are differences, however subtle, there are differences. All of them can be worked around and some OS's have done so. AMD has done a good job of documenting the differences so programmers could/can work around them.
Technology wise, AMD is by far and away a better processor. Intel has sat on thier technology way too long. The P4 is a joke and should have never seen a release day, in its current configuration.
I am very glad to see AMD finally making inroads into the OEM computer makers. This is really good for the market.
If my original post lead some to beleive I was recommending people stay away from AMD, then I apologize, for it was not my intent. AMD makes a good product which is technically superior to anything Intel has to offer, but if you have to run Solaris, or BSD, then you better be using Intel or you will have problems.
I think the only holdback AMD has ever had was the support chips for the processor. Intel does have an edge here as they have been building thier own support chips for a long time. VIA and AMD's recently released support chips have had some problems with maintaining compatibility with Intel support chips. The differences here have remained pretty subtle, but just enough to require changes to some drivers and BIOS code.
If it were just a simple matter of unplugging the Intel chip and putting in an AMD chip, I would be there in a heartbeat, but there is more to swapping from Intel to AMD than a single chip change.
I hope that helps to clear things up.
------------------
Roy "Skuzzy" Neese
President, AppLink Corp.
http://www.applink.net skuzzy@applink.net
[This message has been edited by Skuzzy (edited 02-06-2001).]