Hi again. I was wondering if you could set, say, an AMD K6-2 400 Mhz with a 100 Mhz bus speed to run at 66 Mhz bus speed? Could there be any problems, electrical or stability?
Also, could the reverse be done too? Set a processor with 66 Mhz bus speed to work at 100 Mhz?
Thanks in advance.
It depends on the processor. Some are locked at the multiplier, some at the bus, some both. I believe all K6-2's are unlocked all around. I have two, a 500 and a 475, and both are fully unlocked. No issues with stability, etc. In fact, if you underclock, you can often lower voltage to the cpu so it runs cooler. Just have to test for stability. The other thing to look out for is memory speed. You might try to run a 66Mhz FSB cpu at 100, but if your RAM is 66Mhz, it probably won't work. Some motherboards let you run the RAM and FSB asynchronously, which gives more flexibility and options.
The more I learn, the more I realize how much I don't know.
OPL3 FM vs. Roland MT-32 vs. General MIDI DOS Game Comparison
Let's benchmark our systems with cache disabled
DOS PCI Graphics Card Benchmarks
Yes, it would work either way. The only way you could get problems is if you set the base clock at an uncommon speed like 75mhz or 83mhz. Just make sure if you want to use the k6-2 400 @ 66mhz, you have to set the multiplier to x2.5. This is wired internally to 6x multiplier, makes for easy overclocking if that's your thing.
Ayy LMAO
A base clock like 75mhz will only be problematic for non robust PCI and AGP devices. I ran a K6-2 at 450mhz (6x75) for literally years with no issue and never had a problem with stability, so it's definitely viable.
All hail the Great Capacitor Brand Finder
100 to 66 always, 66 to 100 not always, some chips I've heard just don't cope with the 100 mhz bus at their designated clock speed if designed for the 66mhz bus
CPU always runs at (FSB*Multi). It doesn't matter if FSB is 66 or 100 as long as the multiplier is correct and you're not overclocking it (too much).
Requests are also possible... /msg kixs
Yes, it works. Definitely no problem to run a 100fsb chip at 66fsb but a 66 at 100 could be unstable. I have a locked Pentium 133 which does 200Mhz with a 100Mhz FSB. Lots of flexibility using a super7 boards, lots of fun trying different combinations.
There's also a pin mod for slot 1 boards to run them at 66 even if there's no bios option or jumpers, I do this with a PII 350 if I want to run it at 233 on a no features Intel board.
So that means downclocking is a safe path. I'll have to check if my motherboard does support configuring memory speeds and other things. At least it supports setting Vcore as low as 2.0v.
BTW, mine's a FIC VA-503+. I've read these motherboards are kinda unstable all around so I was a bit concerned about stability.
wrote:CPU always runs at (FSB*Multi). It doesn't matter if FSB is 66 or 100 as long as the multiplier is correct and you're not overclocking it (too much).
no there are more than a few reports of CPU's not handling the 100mhz FSB
wrote:BTW, mine's a FIC VA-503+. I've read these motherboards are kinda unstable all around so I was a bit concerned about stability.
I see that your motherboard has the VIA MVP3 chipset ... If you install the VIA chipset driver, you should be good. Even on newer motherboards (stuff like p3 or athlon), it helped with some issues. On my pentium 3 machine, this enabled the AGP4x and it allowed my radeon 9550 to just ... work X)
Super socket 7 machines are said to have stability issues with AGP, but IMO if you use period correct hardware and the right drivers, you should be good. (I've got a SS7 computer with that chipset and it works great !)
Trying to identify old hardware ? Visit The retro web - Project's thread The Retro Web project - a stason.org/TH99 alternative
wrote:wrote:BTW, mine's a FIC VA-503+. I've read these motherboards are kinda unstable all around so I was a bit concerned about stability.
I see that your motherboard has the VIA MVP3 chipset ... If you install the VIA chipset driver, you should be good. Even on newer motherboards (stuff like p3 or athlon), it helped with some issues. On my pentium 3 machine, this enabled the AGP4x and it allowed my radeon 9550 to just ... work X)
Super socket 7 machines are said to have stability issues with AGP, but IMO if you use period correct hardware and the right drivers, you should be good. (I've got a SS7 computer with that chipset and it works great !)
This machine I got seems pretty stable as it is on Windows 98 SE and I don't plan on changing its parts, maybe adding some but for now it's happy and working flawlessly. I'll try the downclock next weekend and see how it goes. If it goes well I'll also set its multiplier to 2x and check how it performs against some of the older games.
Now I'm trying to figure out if my current BIOS version also supports the K6-2+ and K6-III+ processors in the event I can get ahold of one in the future...
wrote:The K6-2 will happily do what you suggest 😀
https://www.youtube.com/watch?v=fcAqRbFFQPU @ 11:25 <- That CPU does indeed like it 😀
