Epox 8K7A and 1/5 PCI Divider

[webley]

Please post your experiences with the 1/5 PCI Divider on the 8k7a. I just wrote to Epox to ask if the about the 1/5 PCI divider and here is the reply I got:


Sent: Monday, August 12, 2002 10:09 PM
To: support@epox.com
Subject: Does the most recent bios (2529) for the Epox 8k7a have a 1/5
PCI Divider for FSB > 166?


Dear user,
Yes, the latest bios update for the board should have the 1/5 divider.
However the 1/5 divider will be automatically adjust by the bios.

 

[S0me1X]

I'm running the 8K7A+ at 166fsb stably, but I've never tried running at 166fsb with the older bioses.

Does anyone have an idea at what point the board chooses 1/5 over 1/4 multiplier? I'm curious, too.

 

[Alkaline5]

This has been debated ever since the board came out over a year ago. I've never tried it (don't want to fry anything) because there was never any definite evidence one way or the other. Some peoples' boards OC without trouble, others' don't. Personally, I think Epox tech support is just amusing themselves. I hope I'm wrong, though

 

[webley]

Does anyone have an idea at what point the board chooses 1/5 over 1/4 multiplier?

If it kicks in, i've heard it's at 166 or some say 167 FSB. I may try 166, but I think i fried a hard drive once by raising the FSB so i'm a little hesitant to try.

 

[spanky]

hi, i'm new to this 1/5 divider business. whats it all about? i'm just guessing here... does it mean like the pci bus runs at 1/5th of the fsb?

 

[webley]

does it mean like the pci bus runs at 1/5th of the fsb

Right that's what it means. So if the 1/5 divider is working on 166, the PCI is 33 just as it should be. I sure wish the Bios would tell us what the PCI is running at so we could be sure running at 166 isn't overclocking the PCI bus. I'm actually more concerned about the IDE channels and hard drive damage but from what I understand, the divider (if working) would take care of the IDE at the same time.

 

[spanky]

so for those ppl who have a mobo with a 1/4 pci divider... if they run their fsb at 150mhz... their pci bus is at 37.5mhz? if they run at 160, their pci bus is at 40mhz. what r the possible side effects (pro and con) of running the pci bus at 40mhz? will the difference be huge?

 

[webley]

with a 1/4 pci divider... if they run their fsb at 150mhz... their pci bus is at 37.5mhz? if they run at 160, their pci bus is at 40mhz. what r the possible side effects (pro and con) of running the pci bus at 40mhz?

Yes those would be the PCI speeds and that puts extra strain on parts like network cards,hard drives, graphics cards etc but usually they tolerate it. I didn't worry too much about the PCI parts but when my hard drive failed catastrophically, i was kind of sad. The funny thing was that I had only overclocked the FSB a few MHz at the time (133 to about 137) but the hard drive was an IBM 60gxp (sensitive to overclocking FSB). Who knows, maybe the overclock didn't cause the failure because the read head sounded like it hit the disk(s) and those 60gxps have a bad reputation. It's smart to back up your HD frequently.

The benefit of overclocking the FSB is of course the better data transfer rates and the fact that you can reach higher processor speeds than you can when only the multiplier is maxed out (only 12.5 on the 8k7a 12.5x133= only 1662). Also, if you used only the FSB to overclock, you might not have to unlock your processor if it's multiplier is locked (like the Athlon XP). I may have forgotten some benefits/risks but those are the main ones. Just overclocking by multiplier (no FSB) is a much safer way to go if you want to play it safe. Then just the processor will wear out a little faster but other parts aren't at risk. That's how i used to overclock and may do more of even if it means I can only reach XP 2000+ levels (on a XP 1600+ i'm getting to replace a 1.3 Athlon).

 

[Basie]

I never could go beyond 150mz fsb on my 8K7A+ though I never tried the 166mz theory. I have the 8K3A+ now and it wouldnt Post at 134 to 165mz but it's doing fine at 166mz. I lowered the multiplier on
my T-Bird to 9 so I'm running 1.4g@1.5g.