Originally posted by: beefkake
I have an Epox 8KHA+ motherboard. According to their spec sheet, the motherboard supports up to the Athlon XP 2600+ (Thoroughbred) at 266 MHz FSB. Problem is, I'm realizing it's very difficult to find the 2600+ in the 266MHz version (333MHz versino is MUCH more common).
Question: Can I buy a 333MHz FSB 2600+ processor and easily underclock it to 266MHz FSB, so that it runs within specifications on my motherboard?
Appreciate your feedback. Thanks!!
You wouldn't need to "underclock" it if if the 8KHA+ allowed for multiplier adjustments > 13x. You could just run it at 15.5 x 133MHz to get to 2083MHz. The problem is, the Barton will be unlocked with the "low" multis (6x-13x), while you need the "high" multis to run at 133MHz FSB. If you underclocked it, it wouldn't be a problem, you'd just be getting a lot less out of your CPU at 1663MHz (12.5x133MHz), which would put you at a XP 2000+'s stock speeds in the worse case scenario. You'd be able to up that by increasing your FSB, but the 8KHA+ is still limited by a 1/4 PCI divider which will limit your FSB OC'ing efforts. I remember my unlocked 1700+ T-bred A was limited to the low multipliers even though it was unlocked on my 8KHA+; I'm guessing the same holds true for the newer chips as well (its a mobo limitation).
Personally, I would go with a 266MHz FSB XP 2400+ @ 2GHz which will have a 15x multi. This will give you some nice OC'ing headroom with the high divider, and you'll have the flexibility to push your OC w/out much concern for the PCI dividers. Even at stock speeds, you'll have a faster CPU than a Barton running at 133MHz, and if you upgrade in the future to a board that has full multiplier access (KT400A....X,Y,Z or nForce2), you'll be able to take the CPU with you and adjust its FSB and multiplier as well (based on your memory speeds).
Chiz