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5x86 Processor Speed Help

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First post, by whisker58

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I have a Am5x86-P75 (X5-133 W16BHC) that I got from eBay. It's supposed to be a 133MHz processor that has a 4x multiplier. It has a permanent heatsink on a surface mounted 208-pin SQFP, so I can't see the processor markings. I've installed it onto my MV035 Rev D motherboard and set it for an SL AM486DX5 and 33MHz bus speed. But instead of getting the expected 133MHz reported to the system, it shows 120MHz. If I set the bus speed to 25MHz, it'll report 100MHz.

I'm wondering if this is actually a different processor, but the math doesn't make sense. Why would 25MHz x4 = 100MHz, but then 33MHz x4 = 120MHz? Can anyone help, please?

Reply 2 of 4, by red-ray

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What do such as CPUZ, HWiNFO or my SIV utility report ?

They should get it right even is the BIOS does not know about the chip.

Depending which Windows you have there may also be ~MHz in HKLM\Hardware\Description\System\CentralProcessor\0.

Reply 3 of 4, by kixs

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Use CHKCPU or SpeedSYS in DOS to check the actual running speed of your CPU. BIOS can "lie" when the CPU is too "new" for it.

In any case if the above programs report it running at 133, then it will work just fine and there is no need to worry about BIOS.

Requests are also possible... /msg kixs

Reply 4 of 4, by whisker58

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It took a lot of work, but it turned out that the processor is faulty. During my troubleshooting, I also obtained an MV035F which seems to be better suited for these processors. My new processor reports and works perfectly.

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