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View Full Version : k6-III+ performance, overclocking, any real difference?


alex666
05-16-2001, 03:40 PM
I just upgraded my Presario 5220 with an AMD K6-2 380 Mz processor to a K6-III+ 450 Mz processor (had previously added more ram, a new hard drive, and a voodoo 3 2000 pci card). I had read how the K6-III was a significant improvement over the K6-II series. Now, my mobo actually supports the + series, and I was able to set the core voltage to 2.0, and left the I/O voltage at 3.3. The K6-III+ 450 installed flawlessly. I tried to use a larger heatsink, but I had trouble getting it on, and so I simply used the old heat sink and fan. Keep in mind that the core voltage for the K6-II 380 was 2.2. I installed the new processor, no problems, made the correct jumper changes, Sandra identified the processor as a K6II+/K6III+ running at 443 Mz. But I really did not notice any significant improvement in performance, despite all that I read about the K6III. Now, I had read via the AMDzone and Overclockers.com about this utility written by someone named UART. The utility apparently utilizes the special power management instructions written for the K6III+ series (the + series, II and III, were originally intended as mobile processors to be used in notebooks, with these special instructions for power management) such that you can easily overclock. Okay, so I download the utility, try it out, changing the multiplier within this utility (not on the mobo) from 4.5 to 5.0, then 5.5, then 6.0. Sandra tells me it is running at 500, 550, and 600 Mz (actually 493, 543, and 593). The whetsone and dhrystone (sp?) measures used by Sandra increase with each bump in processor speed, indicating that this processor is performing better at these higher speeds.
Two observations: First, the heatsink and processor remain very cool, even after running this thing at 600Mz for over an hour. Is this because the core voltage is 2.0, and actually lower than the original K6II chip? I had read that I should use a larger heat sink, even if I did not overclock, and I did not really intend to do any serious overclocking, but I am finding that I do get somewhat of a boost, and the thing runs cool. What's going on? This is too good to be true. Second, has anyone else upgraded a processor and really not seen a huge difference in performance? I upgraded my original hard drive to a Maxtor 30 gig, 7200 rpm, and immediately noticed a speed improvement, whereas with this processor upgrade, it is much less noticeable despite all I read about the K6III. I don't care that Sandra tells me it is running faster. I want to see it. I have measured boot time, and at 450 Mz, it takes 85", while at 600Mz it takes 77", but otherwise the changes are fairly subtle. What should I be looking for?
Any comments would be appreciated.

hiredgoonz
05-16-2001, 04:15 PM
You're not going to see a huge performance increase, even going from 450 to 600...even though it's a 33% increase in cpu speed, everything else about your system is staying the same...yes the K6-3+ was a huge improvement over the K6-2, but really only brought the chip's performance up to the Pentium 2 level...

The spec. core voltage for the K6-3+ is 1.8V so you're already running it .2V above spec...this is likely the reason it seems stable at the higher clock speeds...when you say you ran it for 2 hours, was this running Windows and web browsing or running something like sandra's burn-in tool?

If your hs is cool it could mean either the cpu is running cool, or the hs is not drawing much heat from the cpu...did you use thermal compound or a thermal pad between the cpu and hs?

An excellent article on this exact topic is at
http://www4.tomshardware.com/cpu/00q4/001106/index.html

I the link doesn't work, go to www.tomshardware.com (http://www.tomshardware.com) and in the cpu section if you scroll down, you'll find an article about socket 7 cpus...

As far as visible performance increase, what exactly do you want? Word or any other program is only going to start so fast, regardless of your cpu speed...your hd still needs to read data to run programs...as long as your cpu is cool for the right reason and you see a speed increase w/ NO stability loss then I would just be happy you can run it that fast...

If your board supports fsb speeds over 100, then you would get more of a performance increase by bumping that up mildly than you will by changing the multiplier, since that effectively overclocks all pci components in your system as well as the cpu...just be careful...the higher out of spec the pci bus is the greater the chance of instability...

alex666
05-16-2001, 04:33 PM
Hiredgoonz, thanks for your feedback. Please note, the core voltage for the k6-iii+ 450 is 2.0, not 1.8. It is clearly stated on the chip itself as well as in a pdf file I downloaded from AMD. As for what programs I ran for the hour I used it at 600 mz, I ran Flight Sim 2000, motocross madness, internet, a variety of stuff. I debated about running the sandra burn in test, but given my concerns about running this thing at 600, I have not done so. And no, I did not use a thermal pad or paste (I can't find any where it live!!) I am aware that a heatsink may remain cool if there is inadequate transfer of heat. However, I have felt along the edge of the cpu itself several times, and it always is cool. Plus, there is no heat in the area of the cpu. Thanks.

hiredgoonz
05-16-2001, 07:54 PM
You're right about the voltage...I was going by the info on tomshardware...I would strongly recommend finding some thermal paste...the edges of the cpu are MUCH cooler than the center where the actual die is located...it sounds like you got a good chip if you can run it 150mhz faster than it's stamped...I don't imagine you want to burn it out...