SystemsSystemsQ. Will my motherboard work with the 6x86MX?
A. Jens Petersen made the following comments in an email that he sent to me:
You repeatedly emphasize that people can use their existing Pentium mainboard for the 6x86MX since the 6x86MX is pin-compatible to the Pentium. I think you forget that the 6x86MX will operate at 2.9V, a voltage that no older Pentium mainboard can provide. Even many of the new mainboards don't offer that voltage.
Jen made a very valid point and I would like to address this comment. I agree that the majority of Pentium motherboards are not P55C (Pentium MMX/6x86L) compatible and will not be to deliver the dual voltage (core 2.9V, I/O 3.3V) that the 6x86MX requires.
Cyrix has repeatedly promised and I have stated many times that people can use their existing 6x86 motherboard to run a 6x86MX with the only requirement being a BIOS upgrade. Many may wonder how this statement can be true if their motherboard is not capable of delivering the proper voltage. If your motherboard does not not have the appropriate dual voltage support you must use a voltage regulator. PowerLeap Products makes a voltage regulator that steps down the voltage to meet the 2.9V core voltage required for the 6x86MX. You can obtain more information about the purpose of voltage regulators and how they are used from their website. There is also a motherboard compatibility list for the 6x86MX provided by Cyrix that you can view on their website.
As of today, Cyrix has no plans for offering a 6x86MX upgrade program to end users. However, Cyrix is working with 3rd party's (ie Evergreen) to provide the 6x86MX in concert with a regulator board and BIOS upgrade for Pentium P54C motherboards that do not support split rail devices.
Q. Will I need a BIOS upgrade before I can upgrade to a 6x86MX?
A. I have always encouraged everyone to do themselves a favor and buy a motherboard from a reputable motherboard manufacturer that has a presence on the Internet. I did this because I knew that you inevitably would want to upgrade your BIOS. With the coming of the 6x86MX, that time is here.
You WILL need a BIOS upgrade to use a 6x86MX if your motherboard does not already support it. The majority of them do not. I know where I will going to get the BIOS upgrade for my Abit AX5; www.abit.com.tw. Do you know where you are going to get yours? Do you even know what brand of motherboard you own? According to my survey results, there are a lot of you who don't. You could soon be paying a high price for deciding to save a couple of bucks and buying a cheap generic motherboard. Good luck identifying, let alone finding, a freebie upgrade for your no-name board.
I suggest you go to Wim's BIOS Page. This is a great site for BIOS information. Included on his site is a page that can help you determine which motherboard corresponds with which BIOS number if you do not know who manufactured your motherboard.
There are no flash bios upgrades available from AMI/Award. AMI/Award gives motherboard manufacturers a BIOS customized for a specific board and chipset. Then the manufacturer, using tools from AMI/Award, makes final modifications to the BIOS before shipping the board. The manufacturer knows more about their motherboard than AMI/Award and is better able to customize it to their needs. That is why you can have an Award BIOS on two similarly equipped motherboards, but the BIOS options are very different.
I also never recommend using a BIOS from a motherboard manufacturer other than your own unless you want to risk rendering your motherboard unusable.
Q. Why does my BIOS misrepresent my 6x86MX microprocessor?
A. Cyrix changed their PR rating definitions after the 6x86MX was released. As a result, a 150MHz 6x86MX could be either a PR166 or a PR200 depending on the bus speed that is utilized. A 150MHz 6x86MX utilizing a 75MHz bus is a PR200 whereas a 150MHz 6x86MX utilizing a 60MHz bus is a PR166.
The problem is that many mainboard manufacturers haven't programmed and released an updated BIOS to reflect the PR rating changes. As a result, many BIOSs will report a 150MHz (75MHz x 2) 6x86MX as a PR166. The BIOS doesn't know better. The chip will still perform as a PR200, however. The BIOS misrepresentation is purely a cosmetic issue and doesn't affect system performance. Contact your mainboard manufacturer for a BIOS upgrade if the misrepresentation bothers you.
Q. Which motherboards do you recommend for use with 6x86MX processors?
A. Check out my Mainboard Recommendations page for my personal favorites. Included on this page are some rules that you should follow when trying to decide which mainboard is best for a Cyrix/IBM microprocessor and my mainboard picks for performance and price.
