Upgrading to AMD K6-2 500MHz

[radman3d2]

I have a Chaintech 5SIM MB with a 400MHz K6-2 (66*6). Can I upgrade to a 500MHz K6-2 (83*6)? I know it is possible, but well it work?

[CMonster]

Honestly - ... it probably will not work because the 83mhz bus speed will overclock your PCI and hard disk drive to the point where the system becomes unstable.

[radman3d2]

I don't think that well be my main problem because I have an async mode of operation. I have overclocked my 400 MHz CPU to 450 (75*6) with no problems, but I'm not so sure 500 MHz well work (83*6,with a new CPU). I have tried using the 83 MHz FSB before and it just isn't stable. I'm not sure why? Chaintech included it, I wonder why it won't work?

[doctj]

If you're using EDO ram that's the reason it's not stable at 83 MHz. A good upgrade is a mobile K6III-450+ which I hear is equivalant to a K6-2 550 in performance if your mobo supports 2.1 voltage. Your memory should tolerate the 75 mhz fsb easily.

[radman3d2]

I have SDRAM (128 Meg) and I tried a K6-3 400MHz and it is not supported.

[CMonster]

Your asynchronous mode may only run your memory at a slower speed.

[Peter M]

Asynch operation on 5SIM (using SiS 5598 chipset) does run PCI at 33 MHz or below regardless of CPU bus speed. RAM bus is always at CPU bus speed.

So what may keep you from going 6.0x 83 MHz? The mainboard's CPU voltage regulators might not be capable of feeding the required amperage, and early revisions of the SiS 5598 don't really run well with K6 family processors above 66 MHz bus, albeit running at 75 or 83 with Cyrixes. This might have been the reason why you couldn't go 83 MHz before. Later revisions of the 5598 were officially 83 MHz capable, and seem to run well at this speed with Cyrix and AMD processors. You might be stuck at 6.0x 75 MHz with what you have there.

Also check what kind of /400 you have - if it's an old AFQ suffix one, then you are probably safe using a /500 as far as the power issue goes - the /400AFQ, being from an older, hungrier manufacturing process, draws almost as much power as does the /500. If it's an AFR, then you don't learn anything from it :-)

Regards, Peter


[This message has been edited by Peter Missel (edited 10-15-2000).]

[radman3d2]

I took a look at the CPU and it is a 400 AFQ. When I do overclock it to 450 I have to up the voltage to 2.6 volts for it to be stable, of course with good cooling. What voltage does a 500 MHz AMD k6-2 run at?

[radman3d2]

Where do you find the new AMD K6-2+ and well it work on my MB?

[bassinvader]

Well I've got a K62-450 (2.4V core 3.3v I/O) is its setting - Think the 500 is the same.
Currently overclocked on a cheapo FIC VA503+ board to 500Mhz with no problems @2.8v - even with EDO ram - Now upgraded to 128 mb SDRAM and tweaked the bios to give 25% more memory speed (Sandra 2000 Pro). Pity I can't change the I/O voltage.
Tried every setting I can think of to get it faster - Lapped the heatsink , new fans in the case , rounded the cabling in the case and even removed the cover and installed venting ducts but I still can't get it faster than 500 - 100Mhz*5Mult.
Think a mobo upgrade is in order Asus A7V???
I don't think a peltier would do me any good - Anyone got any ideas???
The mobo is quite configurable for a cheapie!!!

[sunofwolf]

Buy a DFI ,it will go up too K3 550+= thats my speed now at a mere 2 volts, I lowered it from 2.1 because it was running a little hot= will-see if it can keep this speed up? Last price for a DFI was 72$=its a great board! I just wish it could go to 600 but I bet the chip wouldn't hold up? This is a mobil chip if you get one, DFI =72 and 62$ for chip! 134$ but that much ,I could almost get something else? This is all the speed I need for a while!

[Peter M]

Please guys, no guessing.

K6-2/500 are all 2.2V. The 2.4V K6-2/450 and /475 came from said older manufacturing process that in turn didn't yield at 500.

K6-2+ requires 2.0V (in "standard power" flavor) and must at least have rudimentary BIOS support for the internal L2 cache to work. If a K6-III didn't even work, then forget it - K6-2+ sort of is the K6-III's son.

Regards, Peter

[radman3d2]

Thanks Peter that answers my question. The plus dosn't mean better in my case! I might try a 500 on this MB and if it dosn't work go with a G2, that well be a great stable combo. Thanks again Peter. JW

[Peter M]

The 5SIM is a BabyAT form factor board, isn't it? Changing to an Epox MVP3G2 would mean buying a new case as well.

If you want a modern BAT mainboard with good performance and K6 "+" model support, then your only choice is DFI K6BV3+/66-2. That one has all you can ask for in BAT form factor, UDMA66, 2 MB L2 cache, low CPU voltage support, K6-2+ and III+ BIOS support, fan/temperature/voltage monitors, good AGP implementation, and 2 MB cache.

Regards, Peter

[CMonster]

Leave it to Peter to bring some sanity into it..

Peter could I have a brain transfusion with you?