50 to 133MHz FSB on a BX Mainboard

Discussion about old PC hardware.

Re: 50 to 133MHz FSB on a BX Mainboard

Postby gerwin » 2013-9-05 @ 21:10

Ok. So you are at 600MHz currently. If you are not interested in the speed switching then the benefit is less. Depends on what you want to achieve. Getting a plain 8.0x100MHz CPU may be a lot easier, Whilst getting a tualatin+adapter gives even more speed.

I made a few benchmarks with Quake v1.08, it shows the average FPS.
From pure DOS: Video mode 640x480, timedemo 2, nosound, nojoy.
System: GA-6BXC with Tualeron QID2QS CPU. 128MB RAM. Voodoo3 video, either AGP or PCI variant. AGP divider=2/3.
With and without 'MTRRLFBE LFB WC' (write combining).
Code: Select all
Speed MHz   PCI+WC  AGP+WC  PCI    AGP
4x_50=200   25,9    26,0    13,7   13,7
4x_66=266   34,3    34,4    18,2   18,2
4x100=400   50,5    50,9    25,0   27,0
4x133=533   66,4    67,5    27,0   35,8
8x_66=533   55,7    56,3    21,0   21,1

Edit: added missing benchmark entries
Last edited by gerwin on 2013-9-06 @ 20:32, edited 3 times in total.
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Re: 50 to 133MHz FSB on a BX Mainboard

Postby d1stortion » 2013-9-05 @ 21:27

gerwin wrote:My Geforce MX440 does not like it either. Regarding the other problems, was the PCI bus at 33MHz?

Yes it was. The mobo in question is a CUBX-E, so certainly not some cheapskate board. When I bought it it had an 800EB in it, so I assume the previous owner ran it like that without problems. Or he just settled for 600 MHz, who knows? :lol:
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Re: 50 to 133MHz FSB on a BX Mainboard

Postby idspispopd » 2013-9-06 @ 11:17

Nahkri wrote:Actually it officialy supports the k6 3,and the k6 2+ beeing a k6 3 with 128mb cache,i guess it supports that 1 too :P

The K6-2+ is a K6-3+ with 128kB cache, it needs a lower voltage than a K6-3 and BIOS support to enable all features.
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Re: 50 to 133MHz FSB on a BX Mainboard

Postby gerwin » 2013-9-09 @ 14:58

Yesterday I wanted to see if I can undervolt the Pentium II and III processors. At least for the speeds up to 533 MHz.

The Pentium III Tualatin core (default 1,5V) was on 1,3V already and I have currently no means to lower it further. Works fine even up to 1000MHz. I remember Swaaye wrote about his Tualatin running fine with just 1,1V.

The Pentium III Coppermine core impressed me: SL3VA (default 1,65V) accepted all voltages, it ended up at the lowest setting: 1,3V (measured 1,325V). Let it run Quake for an hour without any problems. I tape-modded the other two coppermine core CPUs (in the picture on the right), as native slot-1 leaves me no jumpers. They behave similar, but need more testing.
The benefit is that they don't really need a fan at 1,3V at 533MHz or less. So up to 533 MHz the Coppermine core is practically the same as a Tualatin core. Making SL3VA, SL3XG and especially the ES more interesting for my use.

Next in line was a Pentium II Deschutes core (default 2,0V). 1,8V with 400MHz was not a reliable combination for the SL2QF. Raised it back to 1,9V which did not cause any problems yet. This processor was originally in the package on the left of it. I removed the package to read the L2 cache specs, and add L2 cache cooling and a new fan.

Also shown is the Pentium II Klamath core SL2HD with its heavy heatsink. Defaults to 2,8V. Maybe I will mess with it later.
Pentium II/III processors for Slot-1
DSC08790_Pentium2-3.jpg (87.4 KiB) Viewed 1953 times
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