Consider this a work-in-progress. More like a warning for the moment.
Yesterday, I worked with a PIV system, the relevant (at this point) details:
Intel 1.6A PIV, Costa Rica, week 8, pack date early April
Asus P4B533-E, BIOS version 1006, beta 1
512Mb Corsair XMS3000 RAM
Western Digital WD800JB hard drive
Enermax EG451P-VE power supply
SENFU Water Cooler II
Setup went without incident. Basic functionality at stock speeds also not an issue. Temperatures with water cooling reached a maximum of 40-41C after running Prime95 at 1.8V, so temperature is not a factor.
Now the overclocking . . . .
Getting up to 2.4GHz caused relatively little problem, though voltage had to be increased about 10% to get the machine stable.
Get the voltage to 1.7V and beyond, and strange things start happening.
Voltage reporting and/or regulation is erratic on the P4B533-E. You put in one setting, the BIOS reports another, PCProbe reports a third.
If you compare the setting you put in to what PCProbe reports, the Asus goes high by about .08V (i.e., put in 1.6V, you get 1.68B).
This is no big deal until you get to 1.7V or better (the Asus board regularly supplies up to 1.7V, and if you set the “overvoltage” jumper, you can go to 1.8V.
I’ve had the board up to 1.82V (per PCProbe), but to do that, I had to do something rather odd. If I just set the FSB to, say, 155, with the high voltage setting, it won’t work.
However, if I keep the voltage high, set the FSB to, say 140, and boot through to Windows; I can restart, reset the FSB to 155, and then it will work.
For the moment, getting past 155 has been a barrier. Sometimes, it just won’t swallow the setting. That I can understand.
Other times, it tells me that Hardware Monitor has found an error. Look, and the only “error” is that the VCore reading is in red. I get that message at 156. I don’t get that message at 155, despite the exact same voltage. That I don’t understand.
I haven’t hooked up sound yet, but others have reported that the Asus also complains audibly when you put a setting past 1.7V.
You might say this particular PIV isn’t the pick of the litter, and there’s probably something to that. You might say the Asus is half-baked on the voltage, and again, there’s probably something to that, too.
However, something else is happening which casts at least a little doubt on the above: 12V readings.
Start pushing the FSB past 150MHz FSB, and the 12V indicators start dropping (again, the BIOS reports one thing, PCProbe reports something significantly different). Actually do something with it, and it drops even more; down to less than 11.6V while (successfully) running Prime95. The higher the FSB, the lower the 12V voltage.
5V readings, on the other hand, are awfully high, about 5.25V.
(This Enermax has a dedicated 12V plug, and I also plugged a power connector into the Asus EZ-Plug, not that it did any good).
A few others have also reported this happening to them. A fellow named GPanda couldn’t get more than 152MHz while suffering the same voltage dropoff, but once he replaced the power supply, he managed to get it up to 163Mhz (look towards the very end of the first page).
So we have three suspects, the CPU, the mobo, and the power supply, and it may be a conspiracy. 🙂
In troubleshooting, when it doubt, separate them out. Generally, the easiest and best way to do that is with spare parts (yours or someone else’s).
Since I was going to need them anyway, a new 1.6A and an Antec TruePower 480 are on its way. That should let me figure out relative guilt and innocence.
Mind you, this was a pretty easy 50% overclock. The problems only start past that point, and I’m hardly done yet.
However, people seem to be having some problems with other 845E and G boards, and are starting to look towards the Asus, and this interim piece was written to tell you that there’s some difficulties here, too, at the moment. You probably want to hold back for a little while.