i acquired a couple athlon xp barton 2500+ cpus (AXDA2500DKV4D): 166mhz fsb, 11x multiplier, 1.65v. what are the chances of getting these to run on the abit or any other kt7a board with the rom.by bios patcher? what about a barton 2500+ with a 14x multiplier?

stanwebber wrote on 2023-11-22, 17:03:

i acquired a couple athlon xp barton 2500+ cpus (AXDA2500DKV4D): 166mhz fsb, 11x multiplier, 1.65v. what are the chances of getting these to run on the abit or any other kt7a board with the rom.by bios patcher? what about a barton 2500+ with a 14x multiplier?

The chances are very good. If it's a late revision chip, unlock the multiplier with the bridge mod (omit this on early revision chips -- the datecode isn't exact, I think it's anything pre 0238). Then just use the pin mod guide. I recommend 16x133 for the 2500+.

If you want to use setmul in DOS with it, modify the bridge to turn it into a mobile (all revisions require this).

I'm having problems with SETMUL on a KT7A rev. 1.0. I tried two different CPUs (XP-M 2800+ Barton and a Athlon Mobile/Palomino) but each time I try to change the multiplier, the system just freezes.
I changed reg 55h/bit2 to 1, but no difference.
Both CPUs work fine on a ECS K7VZA and can be re-clocked on the fly with setmul.
What am I missing here? Is rev.1.0 not compatible with multiplier changes?

pyrogx wrote on 2023-12-03, 20:23:

I'm having problems with SETMUL on a KT7A rev. 1.0. I tried two different CPUs (XP-M 2800+ Barton and a Athlon Mobile/Palomino) […]
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I'm having problems with SETMUL on a KT7A rev. 1.0. I tried two different CPUs (XP-M 2800+ Barton and a Athlon Mobile/Palomino) but each time I try to change the multiplier, the system just freezes.
I changed reg 55h/bit2 to 1, but no difference.
Both CPUs work fine on a ECS K7VZA and can be re-clocked on the fly with setmul.
What am I missing here? Is rev.1.0 not compatible with multiplier changes?

Had the same problem and never found the solution. Now I just change the multiplier in the BIOS.

From the Socket A boards with ISA of my collection (Abit KT7A-RAID V1.0, Abit KT7A V1.3, DFI AK74-EC, Epox EP-8KTA3, Gigabyte GA-7IXE4 and Legend QDI KinetiZ 7EV), I like the Abit KT7A most, both in features and performance. KT133 and KT133A without ISA don't make sense for anyone IMO. I would love to try out the Iwill KK266 or KK266Plus as they are supposed to be good overclockers, with reviews claiming north of 160MHz FSB on reasonable IO voltages (my theory is that they were never sold in Germany as I couldn't find one on eBay in Europe in 2 years. Also, I couldn't find any German reviews of it). On the other hand, the KT133A frequency record on hwbot was achieved on a KT7A at 177MHz, however at a crazy 4.4V IO voltage.
Very few sticks of PC133 will handle that speed. There's Tonicom PC166 Micro BGA memory that doesn't really do 166MHz according to reviews and it is hard to find (managed to score one years ago but looked for a long time). Besides that, Qimonda PC133 sticks seem to overclock well. In general, I recommend at least PC133CL2 modules like Hynix 7ns sticks. This way, one potential cause of instability is ruled out.
My system uses 2x256MB 7ns PC133 memory sticks, Windows 98SE, an Nvidia Quadro FX 3000 AGP (similar to an FX 5900 XT), a Barthon Athlon XP-M 2400+ AXMD2400FJQ4C IDYHA stepping at 12x133=1600MHz 1.25V, Aureal Vortex2 AU8830 PCI and Creative AWE 64 Value CT4520 ISA. I didn't have any problems with the memory but didn't try out more than 512MB because of Win98SE. While some had problems running FX series GPUs on the KT7A on Win98SE, my card has newer caused any problems! Similarly, a 3dfx Voodoo 3 or Voodoo 5 ran well without problems on my board. The Quadro has an external power connector and foregoes the limited AGP power the KT7A seems to have. The PSU is a newer than the capacitor plague with 350W and 20A on 5V. I never recapped my KT7A and all caps look immaculate, so I don't know if I got lucky, they used different caps (brand is Teapo and they appear to be decent) or the previous owner did a recap.
So far, I haven't tried out Setmul or the pinmod to enable higher multipliers. Weirdly, the Athlon refursed to work with the 12.5x multiplier on my board, so I use 12.0x instead.
The flexibility of this platform is awesome for late DOS games up to around 2003. Anything newer runs on Windows XP anyway, so it's my Windows XP PC's territory. I have a hard time deciding on whether to keep the Quadro in the system and use wrappers for Glide games or to replace it with a Voodoo 5. What is your opinion?

Trivia on the Athlon XP Mobile: I read somewhere that they were manufactured until mid-2005 and my particular example is from week 8 of 2005 which I thought is really late for socket A. That information can't be right, as there is a picture on cpuworld of such CPU from week 11 2007! Imagine how late it was produced, only to likely end up in a budget laptop. By that time, the 65nm process was used for other CPUs and 45nm came later that year. 130nm was ancient and the yields and process quality must have been awesome at that point. Who knows how well a 2007 chip will overclock? I guess even better than my 2005 which already is good. So when looking for an XP-M, take the one that was manufactured most recently.

Hi, thanks for the detailed post! I don't have much to add to your excellent advice, except that I too can not go above 512 MB (which is already more than enough). Using both a nVIDIA Geforce 4 in combination with Voodoo 3 PCI works great. The main issue is to find a PSU with a strong 5V rail (at least 25A), old ones have capacitor issues, new ones are weak on the 5V rail. If anyone has recommendations on this, let us know 😀

By the way, a capacitor may look great and be close to failure such as causing a short between ground and Vcc. You cannot verify it with a multimeter while it's on the MB, you need to desolder it and check with the capacitor test of your multimeter. In my experience recapping several boards, the capacitors near the CPU and the AGP port are the ones that go bad, many times with no visual hint at all. With a rare and precious motherboard like the KT7A, it's best to do a full recap. But if you've never recapped, buy a cheap motherboard and hone your skills on it. You don't want to destroy copper traces on the KT7A, it's very difficult to repair.

cde wrote on 2024-04-03, 11:20:

The main issue is to find a PSU with a strong 5V rail (at least 25A), old ones have capacitor issues, new ones are weak on the 5V rail. If anyone has recommendations on this, let us know 😀

I recommend 2 different PSUs that have 24-25A on 5V rail, if that's the minimum you require. They are expensive though:

-Corsair 650 cx650m
-EVGA Supernova 650 G6