I didn't publish the bad news I heard from IBM about 4 weeks ago, because I didn't really want to believe it. Now it seems as if I've been right about it, since things are looking better for the 6x86MX now. These 4 weeks ago I was told that due to manufacturing reasons Cyrix and IBM would only ship 6x86MX CPUs which run at x2 multiplier, 133/66 and 150/75 MHz CPUs, which weren't even announced in the first place. IBM wants me to point out that these were pure yield problems and didn't have anythin g to due with flaws in the manufacturing process. Now it looks as if the yields for the faster and real ones are improving, so that you soon should be able to at least get a PR2 166 (150/60 MHz) and a PR2 200 (166/66 MHz). The PR2 233 (187/75 MHz) will hopefully be in mass production by September, faster clock speeds will follow in Q4 this year.
The currently shipped version of the 6x86MX is revision 1.3.5 and Cyrix/IBM are now testing the new upcoming revision 1.4, which will already be the first shrink. This revision (1.4) should be able to push the yields towards 187 MHz and above.
There also seem some logistic problems that caused IBM being a little bit behind Cyrix in terms of available 6x86MX CPUs. However IBM is ramping up production of their own CPUs as well now. Cyrix asked me to make clear that there is no difference whatsoever in the validation process between Cyrix or IBM CPUs.
The voltage requirements of the 6x86MX have changed from 2.8 V to now 2.9 V. This is valid for Cyrix as well as for IBM.
Cyrix 6x86MX CPUs doesn't show any marking that would tell you the revision number of the chip and they don't seem to be happy about IBM having this 'revision level' marking on their 6x86MX CPUs, which is the last letter in the OEM product number printed on the chip (currently 'A' = revision 1.3). To stay conform with Cyrix, IBM is now considering of not making the revision level coding publicy available anymore as well, although you will still able to see that the revision number must have changed when the 'revision level' letter has changed. In both CPUs you will still be able to read the revision number out via the CPUID registers. However do I have a problem appreciating Cyrix' policy of keeping us more in the dark about their CPU revisions. What do you think?
Here the IBM 6x86MX spec number from the data book:
Since the Computex I haven't heard much of the C6 anymore, which sounds as if they've got problems getting up to 200 MHz versions. These 200 MHz C6 CPUs were promised to several press people including me as soon as they are ready. Obviously they aren't ready yet, which will mean that the end user will have to wait even longer until this CPU will be avilable in the shops.