AMD K6 alternate cclock multiplier settings

[RADAR1797]

Howdy all,

I had a brain storm the other night about AMD clock multipliers and was hoping some folks could help me out. I found out that AMD 'reused' the 1.5 multiplier and made it a 3.5 multiplier. Finding that out was great because I moved my AMD K6 200MHz to 233MHz, but that tops out my motherboard, unless some early AMD K6-II (66 MHz FSB versions) reuse older multipliers as highers ones (i.e. the 2x can be used as 4x). If anyone knows any tricks, I would be highly appreciative.

-RADAR

[This message has been edited by RADAR1797 (edited 04-20-2000).]

[Eli]

I believe the K6-II 400 has it's 6x multiplier remapped to the 2x setting, so it canb e run on a 66MHz system. Watch those voltages though.

[RADAR1797]

Thanks Eli,

I have been perusing the AMD web site, but have not found a 6x multiplier (that doesn't mean it doesn't exist though), but I was wondering if anyone has even tried to take a K6-II at 6x66MHz? If it works and 2x=6x, I would be happy to have a $30 chip upgrade my system.

-RADAR

[CMonster]

It 's a fact, I have done it many times now. the newer K6-2s witht he CTX core have the remapped multiplier 2x=6x.

At this very moment my daughter is next to me playing (edutainment) games using a K6-2 350 set at 2x(6x) 66= 396 (i.e. 400mhz) on an older motherboard. Settings are 2x66 & 2.8v core and 3.3v I/O (the core voltage is a little high, but it is the lowest setting available on this board). I bought a large heatsink/fan and have one additional fan in the case that blows across the CPU. This $49 CPU (and a $39 16MB Voodoo Banshee PCI) has made this old machine a gaming heaven for my 6 year old.

[RADAR1797]

Thank you gentlemen!

I will be purchasing a new processor tomorrow! CMonster, do you have to get the 66MHz flavor of an AMD or will the 100MHz flavor work too?

-RADAR1797

[RADAR1797]

Ok, I ordered a AMD K6-III 400 for $83 that should be hear Tuesday. I figured with only having 512K onboard L2(3) cache, that the extra forty bucks for the K6-3 would be worth the money. I'll pop that bad boy into my system and tell you how it goes.

-RADAR

[800XL]

1.5 = 3.5x was actually true of the Intel Pentium W/MMX chips as well.

[alpha]

Any K6 will do it. I suggest a K6-2/3 400, 2x(6x) mult and 66mhz bus.

[OSPA]

I have K6 and I don't have 2x multiplier, only >3.5. Why?

[RADAR1797]

OSPA,

What motherboard do you have? Mine is over two years old, so is setup for Pentium 133s still. Does your MB have a 100MHz setting for the FSB or a 6x multiplier built in?

-RADAR

[OSPA]

Intel Triton 430TX (chip, I don't know anything else)
Multipliers max 5
BUS is max 83MHz

[This message has been edited by OSPA (edited 01-03-2000).]

[RADAR1797]

OSPA,

You can use 5*75 for 375MHz or 5*83 for 415MHz. Sounds like your board is even more capable than mine is. I'll post if my AMD K6-3 works on Thursday, if so go out and get yourself a new CPU and save lots of money on essentially a new machine.

-RADAR

[OSPA]

I can't get the USB speed over 68.5. I have tried 5x75 and 83x4.5 (with 2.4v, that's the highest that my motherboard gives) and with both settings, it gets to the Win98 start-up logo and crashes. I think that it would run with 2.5v, but I can't give that to it so...

[OSPA]

Model=7
Speed=300MHz

[RADAR1797]

OSPA,

Ok, your system may not make it up to 375. Try using a 5*66 setting to give you 333. If that works, then try 4.5 * 75 to give you 338. Leave it there for a while and let it burn in for a bit. Unfortunately, many times when AMD or INTEL reach the end of a CPU run (ie the K6-300MHz was the last K6 produced), the margin for overclocking is pretty low. The good news is for $30 you can buy a AMD K6-II 400MHz and for $67 a K6-3 400MHz. Let us know it is going.

-RADAR

[OSPA]

I can't put the BUS to 75 (or 83). It just gets to the Win98 logo and the stops. I had it at 343MHz (68.5x5 2.3v) for a while. No problems. Now I have it at 300MHz.

[RADAR1797]

Sorry to say it, but 68.5 * 5 seems to be your max with that CPU. Have you thought about getting a K6-2/3 400 or 450?

[CMonster]

RADARI,

1) No you don't have to get the 66mhz version.

2) I hope your K6-3 doesn't disappoint you. Although I'm fairly sure that the K6-3 does have the remapped multiplier I am not so certain that it is compatible with every older motherboard and BIOS. In addition, I believe that the K6-3 is more sensitive to over-voltage, so there is more risk involved with higher core voltage.

I also heard (but do not know for sure) that in older BIOSs you should turn off the on-chip (L1) cache option when installing the K6-3 because it's on-chip cache is controlled internally (not substantiated).

[This message has been edited by CMonster (edited 01-05-2000).]

[RADAR1797]

OSPA,

What model and speed of K6 do you have?

-RADAR

[RADAR1797]

Cmonster,

Thanks for the heads up. If it doesn't work, it will be a good excuse to get a new motherboard. I think I will be ok on the voltage side, I have a 2.5v setting, which is only .1 over the rating for the chip. My K6-3 comes in tomorrow, I'll let you know how it goes.

-RADAR

[Andy_L]

If disabling the L-1 cache doesn't help, try enabling L-1 then disabling L-2.

[OSPA]

RADAR

I think I'm just glad that I can't damage my components anymore. Actually I was thinking of buying a new processor, but I think I'll try the Athlon when I get enough money (then after that I should buy a new motherboard, new hard disk and more RAM).

[RADAR1797]

OSPA,

I know that feeling, I get enough for a new processor & MB, then that old HD and Vcard are no longer good and after a few hours of talking yourself into spending money you don't have, you have ordered a sweet system that blows everyone out of the water for a week. God love capatilism :-)

BTW, my processor is in Kentucky on the path to Georgia and should be to me tomorrow afternoon.

-RADAR

Oops added added the wrong pic :-)

[This message has been edited by RADAR1797 (edited 01-05-2000).]

[RADAR1797]

Ladies and Gentlemen,

I am sad to announce that my pipe dreams of running a K6-III 400 on my old PCChips M537 motherboard were officially dashed today. I need to look at AMD's website again, but they made no mention of a 2.2v version of their chip, only the 2.4v. The poor thing would not even POST. I put my AMD K6-200 o'clocked to 233 back in and will be looking for a reasonable Socket 7 AT motherboard. Anybody have any suggestions? If I can, I would like to overclock this chip to 450.

-RADAR

[Krueger81]

Try the New FIC VA-503+ ver 1.2A I had the older FIC-503+ and it rocked with its 1 MB Cache I could clock my AMD K6-2 300 to around 350 which is allright I guess. Good luck that board is around $70+ shipping at pricewatch.com www.pricewatch.com/ (http://www.pricewatch.com/)

Hope I helped you get back to me with an e-mail when you have the new board maybe I can help you out a little I used to have an AMD CPU

Sorry got the URL wrong http://www.sysopt.com/forum/smile.gif
DAMM UBB code http://www.sysopt.com/forum/smile.gif




[This message has been edited by Krueger81 (edited 01-06-2000).]

[RADAR1797]

Krueger,

Thanks for the suggestion, the FIC happened to be one of the boards I had narrowed down too. I'll let you know how it goes.

-RADAR

[Symes]

Radar,

Do you think it's the overvoltage or the BIOS?

Is your M537 actually a 537DMA? If so you can easily modify it to get 2.3V - have a look at my site www.zarniwoop.force9.co.uk (http://www.zarniwoop.force9.co.uk) .

FYI - I've had email from people running K6-2s at 6x83 on the 537DMA. All we need now is AMD to start remapping the 2.5,3 and 3.5 to give 6.5,7 and 7.5 multipliers and we can really fly!

Symes.

[neo_otyugh]

the FIC va-503+ is a great board i used to ahve one until a faulty power supply cooked it

right now i am using a gigabyte ga-5ax and it has ben very good as well...i am overclocked from at 473 from a k6-2 400
i like the gigabyte also because it is an ATX board...

[RADAR1797]

Symes,

Alas I only have the M537 with the VXPro and not the 537DMA with the VXPro+ I looked at your site though and found it to be very interesting. Thanks for the info!

-RADAR

[Pulsar]

i have an asus p5a motherboard. i have had very good luck with it. i have been able to take a k63-450 to 550 at 100,5.5 and to 517 at 115,4.5. that really cooked. ran better than at 500 because the whole motherboard was overclocke. i got my for about 115 and have really beat on it. ive been trying watercooling and have had a few spills. but it has not killed anything on the board yet. just the cpu. i am impressed.

you get a new board and you should be able to hit 450 very easily.

[RADAR1797]

Howdy all,

Ok, I have some new developments. After being out of the country for a few months, I decided to see if I could get that old K6-3 to work on my old MB. This time when I put it in though, I forget to change the settings from my K6 233, and when it booted low and behold it came up with saying it was a

-66 MMX

Not being discouraged, I loaded Windows and checked out what CPUID said...Whoop it stated AMD K6-III 233! So then I changed the jumper settings to 6 X 66 MHz...the computer wouldn't even POST. Then I tried 6 X 50 and it worked fine at 300 MHz, so I was inspired to try 6 X 60, which again wouldn't POST. Luckily I have a 55 MHz setting and set it to that and she is now running at 330 MHz.

CMonster, could you tell me how to know if I need to disable the L2 or L1 cache? And if anyone could tell me why my MB will not let me set my FSB higher than 55 MHz with a 6 multiplier I would be grateful.

Thanks,

RADAR

[This message has been edited by RADAR1797 (edited 04-20-2000).]

[Peter M]

Radar,

your old mainboard might just be unable to feed the K6-III beast when running at its full speed. K6-III/400 2.4V requires about 12.5 Amperes, 2.2V types are slightly above 10. If you take a 2.4V model and run it 2.5V, that adds even more.

Now with old mainboards either having 5 Amperes capable linear regs, or 8 Amperes switching regs (10 if you're really lucky), the K6-III might just starve. (What happens is that with the voltage regulators overloaded, regulation quality goes beyond the +.1V/-.1V tolerance, affecting stability so much that it won't even POST.)

The "-66MMX" display is because your BIOS doesn't know the CPU type, and also doesn't display a core speed in that case, just the mainboard speed.

Regards, Peter

[cpucook]

I ran my K6-2 450 on a old SIS mobo. I used 2.0x75 to get 450. The voltage goes from 2.0v and skips up to 2.6v....so I had to use 2.6v to get a boot.
The strange thing is, this mobo has no documentation for CPU's above 300Mhz, and DEFINATELY has no K6-2 support, but it ran stable with Win98.
If the mulitplyer adjustments are available....you might get it to run :-)

[RADAR1797]

Thank you for your assistance gentlemen. Peter I think you are dead on with the power issue. I am using a super cheap MB (PC CHIPS M537) that I am sure was not designed to provide any more than it needed to back when it was built. As for the BIOS, not knowing what CPU it is does not bother me.

The thing I would still like to know about is this issue with the L2/L1 cache and if I need to turn one or the other off?

Thanks,

RADAR

[RADAR1797]

Ok, now I have an interesting question for you guys. Peter, would my MB be able to handle a K6-2 400? If so, would I be better running a K6-2 66X6 (396) or keep my K6-3 underclocked at 55X6 (330)? Opinions appreciated.

-RADAR

P.S. CMonster, do you have any info on the L1/L2 cache settings?

[Shazam!]

I thought the K6-3 used the motherboard's L2 cache as an L3 cache since it has an internal L1 and L2 cache. I would keep the L3 cache enabled.

Have you tried using any CPU benchmarking programs to see the difference in cache combinations? I know Sysoft Sandra has a CPU test but I'm sure there are other one's out there.

[RADAR1797]

Ok, I did the test. BTW, a processor without cache is about worthless. At least for my MB (PC Chips 537), you do not need to turn off the internal cache. In fact if you do, you take a huge performance hit.

-RADAR