First post, by squelch41
I need some help!
The aim - to get a 933MHz Pentium 3 1.75v CPU stable.
motherboard - msi 6119 440bx
- a 'proper' slot 1 450Mhz pentium 3 2.0v katami 100mhz fsb
- a celeron 1.75v  1.1GHz 100mhz fsb  - SL5XU
- a pentium 3 1.75v 933MHz 133 fsb  - SL5U3
- 2 slockets - slocket 'a' is a PGA slocket modified to take FC-PGAs. Has a block of jumpers to set voltage. Slocket 'b' is an FC-PGA compatible slocket without voltage jumpers
1 stick of PC100 256mb
1 stick of PC133 256mb
1 stick of PC 133 128mb ram though it crashes the machine if the FSB speed is at 133MHz so pretty sure this is a bad stick
I can get the 450MHz P3 to do:
450MHz at 100Mhz FSB, it works fine with a 112MHz FSB and, with the L2 cache off, the machine run at 133MHz FSB. Memtest completes with the PC133 256mb ram stick without errors (and at 122 and 100). The PC133 128mb stick crashes the machine instantly (and no POST) with a 133 MHz fsb
If I use the slocket a with any of the ram sticks (only using sticks individually)
The celeron is stable up to 112MHz FSB. Instant crash if try 133MHz. The celeron is unstable if the FSB is set to 100MHz (crashes on 2nd post screen) or 103MHz
If the jumper on the slocket is set to "overclock" rather than "auto", the bios then offers up 66MHz, 75MHz and 83MHz FSBs -- it is stable on all of these.
The pentium 3 933 will not POST if the slocket jumper is set to "overclock" but if the bios is set to 83MHz and then it is put into the slocket, it's stable.
It isnt stable at 133MHz in that there are glitches in games. at 112MHz I have got it to run games but it is is prone to crashes.
memtest always fails in bulk transfer tests - instantly at 112 MHz when it reaches the bulk transfer test and at the end it is all errors at 133MHz of the bulk transfer test.
I did manage to get it through 3dbench2001 before it crashed and at 112 and 133Fsb it significantly outperformed the celeron (which is why I'd like to get it working)
If I use slocket b:
With the PC133 256mb ram:
The 933 is stable with 100MHz fsb but frequently fails to get beyond POST at 112Mhz and doesnt post at 133MHz
The PC seems to undervolt - it only feeds about 1.68v (same is true if I use the 'auto' voltage setting on slocket a). I therefore modified the slocket so that VDD1 (I think it was) is held to VCC - now the core voltage is 1.8v
However, it is still just as unstable.
The celeron is unstable at anything 100Mhz or above.
Slocket B has a 2 jumpers only - 1 that is closed witha solid link but can be opened for cyrix cpus, then another that is for "cyrix 100MHz fsb" which I have tried open and closed but makes no difference.
There were also some unpopulated pads marked "CE1" and "CE2" that looked like they were for electrolytic caps that werent populated, so in case they added stability, I added a 10uF capacitor to each but that made no difference either
I am using a farily large akasa cooler for the slockets CPUs so I dont think they are overheating
Ram timings are all set as loose as possible (to "3" and with spectral [thing] set to "off")
I am pretty sure the PC133 256mb stick is good as it passes memtest etc fine with the P450 at every speed.
The 9250 AGP card and PCI cards seem fine with the overclocks given the P450 is stable at all speeds (with L2 cache off, with it on, it just crashes instantly at 133MHz)
The motherboard seems good given that the P450 works unless it is that the power delivery is marginal and the extra power needed for the P3 933 and celeron tips it over the edge? There are no obviously bulging caps on the motherboard. Slocket A has a couple of electrolytic caps, B has none except the new ones I added.
I have spent ages trying to work out why I cant get the pentium 3 running stably at 112 or 133 MHz fsb and why memtest keeps failing at the block transfer stage.
Can anyone shed any light on this!
V4P895P3 VLB Motherboard and AMD 486 133MHz CPU
64mb RAM, CF 4Gb HDD,
Realtek 8019 ethernet + XT-IDE bios ROM, ES1869 soundcard, VLB multi-io card Cirrus Logic GD5428 1mb VGA
440bx MSI 6119, modified slocket , celeron 1.1GHz, 256mb SD-RAM, CF 4GB HDD